D — https://cas.cn | BeaverCheck Audit

Site Health

Score: 66 / 100

Based on 8 categories, 0 sections

Decent speed, but optimizing further could improve engagement.

Several missing protections leave your users and data exposed.

Major barriers for users with disabilities — up to 15% of your audience.

Well-optimized for search — your content is discoverable.

Good server performance with room for optimization.

Several regulatory requirements are not yet met.

Missing metadata means poor previews on social media and search.

Heavier than average — reducing page weight saves energy and bandwidth.

How is this calculated?

The overall score is a weighted average of individual category scores. Categories with more impact on user experience and security carry more weight.

Performance 25%Security 25%Accessibility 15%SEO 10%Infrastructure 10%Compliance 8%Content 5%Sustainability 2%

Weights reflect general web best practices. Individual needs may differ.

How the composite score is calculated

How you compare

jQuery · 1027 peers

You 66

Avg 73

-7 below average

0 50 100

See full jQuery benchmark →

Swiper · 291 peers

You 66

Avg 72

-6 below average

0 50 100

Better than 1% of Swiper sites See full Swiper benchmark →

Top Priorities (5)

Content-Security-Policy header is missing

Security gaps expose your site and users to attacks, eroding trust.

Security › Security Headers

HSTS header is missing

Security gaps expose your site and users to attacks, eroding trust.

Security › Security Headers

No Content-Security-Policy header found

Security gaps expose your site and users to attacks, eroding trust.

Security › Content Security Policy

Page weighs 8.9 MB (8.9 MB transferred)

Performance issues directly impact user engagement and conversion rates.

Performance › Page Weight Budget

106 image-in-link without alt text

Accessibility issues exclude users with disabilities — up to 15% of your potential audience.

Accessibility › Alt Text Quality

View fix priority matrix

Fix Priority Matrix

5 findings

Impact

Quick Wins

High impact, low effort — start here.

Strategic

High impact, requires investment.

Easy Improvements

Small gains, minimal effort.

Nothing in this quadrant — good news.

Deprioritize

Low impact, high effort — do last.

Nothing in this quadrant — good news.

← Low effort High effort →

Embed this badge

Markdown

[![BeaverCheck](https://beavercheck.com/badge?url=https%3A%2F%2Fcas.cn)](https://beavercheck.com/results/eadb21d1-631d-4ef5-bfa3-537705b35aa1)

HTML

<a href="https://beavercheck.com/results/eadb21d1-631d-4ef5-bfa3-537705b35aa1"><img src="https://beavercheck.com/badge?url=https%3A%2F%2Fcas.cn" alt="BeaverCheck Score"></a>

Image URL

https://beavercheck.com/badge?url=https%3A%2F%2Fcas.cn

This badge auto-updates with your latest scan result.

What fixing these means

Your site has several issues that may be affecting user experience and business outcomes. Your LCP of 7.6s exceeds Google's 2.5s 'Good' threshold and the 1 performance issue below directly contributes to it. Accessibility issues exclude users who rely on assistive technology — an estimated 15% of your potential audience. Addressing the critical issues below would have the most immediate impact on your user trust.

3 security gaps detected — browsers may warn visitors about your site.

Your LCP is 7.6s — fixing the 1 performance critical could bring it under Google's 2.5s 'Good' threshold.

1 accessibility issue excludes users who rely on assistive technology.

Could reach Estimate based on resolving critical issues

Conversion Barriers

3 critical 7 warning

10 barrier(s) likely increasing bounce by ~33%.

Speed (1)

Page takes 7.6s to load

+12% bounce

Users abandon at ~3s — you're 5.1s over the 2.5s threshold

Fix: Optimize render-blocking resources, preload the hero image, and compress images

Trust (2)

No HSTS header

+1% bounce

Returning visitors are briefly exposed to downgrade attacks on first request

Fix: Set Strict-Transport-Security: max-age=31536000; includeSubDomains

No Content-Security-Policy header

+1% bounce

Higher XSS blast radius — one compromised script can exfiltrate the checkout form

Fix: Ship a reporting-only CSP first, then enforce once violations are clean

Usability (2)

9 form field(s) without a label

+6% bounce

Screen readers skip unlabeled fields; autofill can't identify them; checkout abandonment spikes

Fix: Associate every input with a visible <label for="…">; add autocomplete attributes

Viewport disables user zoom

+2% bounce

Visitors with low vision can't read the page — and some jurisdictions treat this as a legal risk

Fix: Remove user-scalable=no; drop maximum-scale if it's below 2

Content (2)

No Open Graph tags

+2% bounce

Links shared on LinkedIn / Slack / Facebook show bare URLs — referral clicks drop

Fix: Add og:title, og:description, og:image, og:url to the page head

No structured data

+2% bounce

No rich-result eligibility in Google — lower SERP CTR vs competitors with stars and prices

Fix: Add JSON-LD for your page type (Product, Article, FAQPage, LocalBusiness, …)

Navigation (3)

48 link(s) with generic text ("click here", "read more")

+1% bounce

Screen-reader users navigating by link list see no context — and search engines can't infer relevance

Fix: Rewrite with descriptive phrases that identify the destination

No skip-to-content link

+1% bounce

Keyboard and screen-reader users must tab through the entire header on every page

Fix: Add a visible-on-focus <a href="#main">Skip to content</a> as the first focusable element

7 broken link(s) on the page

+5% bounce

Clicks land on 404s — trust drops and the session often ends

Fix: Fix or remove the broken destinations surfaced on the Content tab

Preliminary CRO audit — each barrier links to the tab with detailed analysis.

Return on Investment

¥1,750 investment → ¥21,182/month returns + CNY 50,000,000 risk avoided

Payback period: < 1 month First-year ROI: +14425%

Investment

¥1,750

5h · 5 findings

Monthly returns

¥21,182 /mo

~¥254,186 / year

Conversions recovered ¥21,166
Bandwidth savings ¥16

Regulatory risk avoided

CNY 50,000,000

if kept compliant

PIPL CNY 50,000,000

Payback period

0 12mo 24mo

¥525 — in quick wins — start here for the fastest payback

Figures combine localized regulatory fine ceilings, search/conversion value priced against local CPC, and bandwidth waste estimates. Results depend on implementation quality and audience composition. Not legal or financial advice.

Full methodology & sources

Estimated Remediation Cost

¥1,750

5.0 developer hours at ¥350/hr

Based on China rates (¥350/hr)

Quick wins

¥525 3 fixes in ~90 minutes

Start here for the best return on investment

Cost by category

Cost by effort level

Adjust assumptions

Custom rate

¥ /hr

Rates reflect fully-loaded developer cost including overhead

How developer rates are sourced

What Inaction Is Costing You

¥4,166,683 / month at risk

~¥50,000,191 / year if left unfixed

Compliance Risk

¥50,000,000

PIPL

No privacy policy link detected
PIPL: CNY 100,000 – CNY 50,000,000
Privacy Policy not detected
PIPL: CNY 100,000 – CNY 50,000,000

Bandwidth Waste

¥16 /mo

27922.7 MB/mo × 0.571 CNY/GB

Optimize transfer: save ~2.8 MB per page load
Saves ¥16/mo

Compliance figures represent the statutory maximum fine for the most severe triggered category, capped per regulation — not the sum of per-finding penalties. Based on published regulatory fine ranges. This is not legal advice.

Compliance methodology · SEO assumptions · Bandwidth model

Your performance is already good — improvements may show diminishing returns

Monthly visitors

Unique monthly visitors from your analytics

Conversion rate (%)

Purchases, signups, or key actions

Avg. order value

Optional — for revenue estimation

additional conversions/month

more engaged visitors from reduced bounce

potential monthly revenue

Current bounce (est.)

After fixes (est.)

Estimated bounce reduction

Fix 5 critical issues to capture this value

How this is calculated

Based on Google/Deloitte research ("Milliseconds Make Millions") showing a ~7% bounce rate increase per additional second of LCP above the 2.5s "Good" threshold.

Your site's LCP: → estimated after fixes.

These are estimates based on industry research — actual results vary

Bounce-rate model & assumptions

Your data stays in your browser — nothing is sent to our servers

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Lighthouse Scores

Industry-standard audits powered by Google Lighthouse.

Performance

Accessibility

Best Practices

SEO

Core Web Vitals

Key metrics that affect user experience.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

3.66 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

7.56 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

0 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.054

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

15.28 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

7.56 s

Detailed Report

Audit breakdown by category with detailed findings.

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

Why this matters

Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.

Learn more ▾

Most users today run browsers that natively support ES6+, async/await, optional chaining, and the rest of modern JavaScript. Transpiling to ES5 'just in case' adds 20-40% to your bundle for no benefit. Configure your build to target a modern browserslist, or ship a differential bundle pair (modern + legacy) with the module/nomodule pattern.

Source: Google web.dev / Lighthouse

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Request	Cache TTL	Transfer Size
www.cas.cn/gd/202603/W020260320367237873144_ORIGIN.jpg	0.0 ms	622.6 KiB
www.cas.cn/gd/202603/W020260304562615519478_ORIGIN.jpg	0.0 ms	456.8 KiB
www.cas.cn/yx/202603/W020260324417741201243.png	0.0 ms	454.2 KiB
www.cas.cn/gd/202603/W020260320373519199299_ORIGIN.jpg	0.0 ms	387.9 KiB
www.cas.cn/gd/202603/W020260305339535003381_ORIGIN.jpg	0.0 ms	366.7 KiB
www.cas.cn/gj/202604/W020260421522038092312.png	0.0 ms	350.4 KiB
www.cas.cn/cm/202604/W020260421385309959198.png	0.0 ms	280.4 KiB
www.cas.cn/newmedia/dsp/202604/W020260420329652831168.png	0.0 ms	269.6 KiB
www.cas.cn/sygz/202604/W020260416563069960778.png	0.0 ms	267.7 KiB
www.cas.cn/gd/202603/W020260304562615738276_ORIGIN.jpg	0.0 ms	266.8 KiB
www.cas.cn/gd/202603/W020260305339535231140_ORIGIN.jpg	0.0 ms	233.6 KiB
www.cas.cn/gd/202601/W020260128305083603703_ORIGIN.jpg	0.0 ms	230.0 KiB
www.cas.cn/spx/202604/W020260420379180266731_ORIGIN.jpg	0.0 ms	217.0 KiB
www.cas.cn/images/z19_ewm3.jpg	0.0 ms	215.4 KiB
www.cas.cn/gd/202603/W020260303457407403045_ORIGIN.jpg	0.0 ms	212.4 KiB
www.cas.cn/spx/202604/W020260417530461254188_ORIGIN.jpg	0.0 ms	206.3 KiB
www.cas.cn/yw/202604/W020260414668107692283_ORIGIN.jpg	0.0 ms	192.9 KiB
www.cas.cn/images/20260309_navkjqk.png	0.0 ms	187.3 KiB
www.cas.cn/newmedia/dsp/202604/W020260421546988627746.png	0.0 ms	167.1 KiB
www.cas.cn/syky/202604/W020260421315832007785_ORIGIN.jpg	0.0 ms	141.8 KiB
www.cas.cn/images/20230731zcjd.jpg	0.0 ms	129.0 KiB
www.cas.cn/gd/202601/W020260121576547305038_ORIGIN.jpg	0.0 ms	123.3 KiB
www.cas.cn/images/z19_foot_m.jpg	0.0 ms	122.8 KiB
www.cas.cn/gd/202601/W020260121572218060263_ORIGIN.jpg	0.0 ms	121.2 KiB
www.cas.cn/gd/202603/W020260303457407615596_ORIGIN.jpg	0.0 ms	120.0 KiB
www.cas.cn/gd/202601/W020260128305083857947_ORIGIN.jpg	0.0 ms	118.4 KiB
www.cas.cn/lib/css/hover.css	0.0 ms	116.2 KiB
www.cas.cn/spx/202604/W020260418314827276324_ORIGIN.jpg	0.0 ms	115.0 KiB
www.cas.cn/lib/js/plugin/wza/esdtoolsinit.js	0.0 ms	100.9 KiB
www.cas.cn/lib/js/jquery.min.js	0.0 ms	95.1 KiB
www.cas.cn/zt1/202604/W020260401410085460301.jpg	0.0 ms	94.8 KiB
www.cas.cn/images/swiper.min.js	0.0 ms	94.4 KiB
www.cas.cn/zt1/202603/W020260320378579484579.jpg	0.0 ms	88.3 KiB
www.cas.cn/images/zjzkymob_202303.jpg	0.0 ms	86.4 KiB
www.cas.cn/zt1/202604/W020260401410081532588.jpg	0.0 ms	82.5 KiB
www.cas.cn/zz/yld/201605/W020190929739561066807.jpg	0.0 ms	81.1 KiB
www.cas.cn/kxyj/202512/W020251218633030399800.jpg	0.0 ms	75.0 KiB
www.cas.cn/zz/yld/201704/W020190929738332637068.jpg	0.0 ms	73.3 KiB
www.cas.cn/kxyj/202512/W020251218541107090958_ORIGIN.jpg	0.0 ms	71.2 KiB
www.cas.cn/images/zjxbmob_202303.jpg	0.0 ms	70.6 KiB
www.cas.cn/images/z19_kxyj_img2.jpg	0.0 ms	69.7 KiB
www.cas.cn/syzc/202312/W020231229530488598921_ORIGIN.jpg	0.0 ms	56.4 KiB
www.cas.cn/images/z19_tj_img1.jpg	0.0 ms	53.2 KiB
www.cas.cn/zz/yld/201803/W020191125383560116474.jpg	0.0 ms	49.3 KiB
www.cas.cn/images/zjzkypc_202303.jpg	0.0 ms	47.3 KiB
www.cas.cn/lib/js/plugin/swiper/idangerous.swiper.min.js	0.0 ms	44.4 KiB
www.cas.cn/kx/202404/W020240510574946875857_ORIGIN.jpg	0.0 ms	43.9 KiB
www.cas.cn/zz/yld/202504/W020250416559005659783_ORIGIN.jpg	0.0 ms	40.3 KiB
www.cas.cn/images/zkyzsmob_202303.jpg	0.0 ms	38.8 KiB
www.cas.cn/images/z2025_dqgz1.jpg	0.0 ms	37.9 KiB
www.cas.cn/images/z19_dqgz2.jpg	0.0 ms	37.4 KiB
www.cas.cn/zz/yld/202308/W020240329553856002424_ORIGIN.jpg	0.0 ms	36.5 KiB
www.cas.cn/zz/yld/202409/W020240912524118761361_ORIGIN.jpg	0.0 ms	36.2 KiB
www.cas.cn/images/dsb02_20251217.png	0.0 ms	36.0 KiB
www.cas.cn/zz/yld/202404/W020240407367171999355_ORIGIN.jpg	0.0 ms	34.7 KiB
www.cas.cn/images/zjxbpc_202303.jpg	0.0 ms	34.5 KiB
www.cas.cn/zz/yld/202504/W020250406365313605807_ORIGIN.jpg	0.0 ms	34.0 KiB
www.cas.cn/zz/yld/202311/W020231122659760924736.jpg	0.0 ms	33.6 KiB
www.cas.cn/zz/yld/202504/W020250406366075798999_ORIGIN.jpg	0.0 ms	31.3 KiB
www.cas.cn/zz/yld/201909/W020201118270525579945.jpg	0.0 ms	30.5 KiB
www.cas.cn/kx/202404/W020240510575174145626_ORIGIN.jpg	0.0 ms	29.0 KiB
www.cas.cn/images/z19_styleMobile.css?v=1.0	0.0 ms	26.9 KiB
www.cas.cn/images/z19_public.css?v=20251218	0.0 ms	24.6 KiB
www.cas.cn/newmedia/dsp/202604/W020260421276040437486.jpg	0.0 ms	23.5 KiB
www.cas.cn/images/20220826kejitop.jpg	0.0 ms	23.3 KiB
www.cas.cn/cg/112072/images/P020190929620050824644.jpg	0.0 ms	22.8 KiB
www.cas.cn/images/yjzxgl_202203826.jpg	0.0 ms	21.4 KiB
www.cas.cn/lib/js/plugin/swiper/swiper.min.css	0.0 ms	19.5 KiB
www.cas.cn/images/dsb01_20251217.png	0.0 ms	18.2 KiB
www.cas.cn/images/z19_logo.png	0.0 ms	16.3 KiB
www.cas.cn/images/z19_tj_img3.jpg	0.0 ms	15.2 KiB
www.cas.cn/images/z19_school_bar1.jpg	0.0 ms	13.8 KiB
www.cas.cn/images/z19_index.css?v=20251225	0.0 ms	13.2 KiB
www.cas.cn/images/z19_main.js?v=1.0	0.0 ms	13.0 KiB
www.cas.cn/images/z19_school_bar3.jpg	0.0 ms	12.3 KiB
www.cas.cn/images/z19_stylePad.css	0.0 ms	12.1 KiB
www.cas.cn/images/z19_school_bar2.jpg	0.0 ms	11.7 KiB
www.cas.cn/images/z19_school3.jpg	0.0 ms	10.3 KiB
www.cas.cn/images/z19_school2.jpg	0.0 ms	9.5 KiB
www.cas.cn/images/z19_school1.jpg	0.0 ms	8.0 KiB
www.cas.cn/images/z19_close.png	0.0 ms	6.3 KiB
www.cas.cn/images/z22_jl_xfqd.png	0.0 ms	5.3 KiB
www.cas.cn/images/z19_jl_icon4.png	0.0 ms	5.2 KiB
www.cas.cn/images/z19_index_yw2.png	0.0 ms	4.6 KiB
www.cas.cn/images/z19_jl_icon2.png	0.0 ms	4.6 KiB
www.cas.cn/images/z19_gopc.png	0.0 ms	4.4 KiB
www.cas.cn/images/jiucuo.png	0.0 ms	4.1 KiB
www.cas.cn/images/z19_jl_icon5.png	0.0 ms	3.7 KiB
www.cas.cn/images/wza_2024.png	0.0 ms	3.3 KiB
www.cas.cn/lib/js/plugin/jquery.cookie.js	0.0 ms	3.3 KiB
www.cas.cn/images/z19_scroll_wb.png	0.0 ms	3.2 KiB
www.cas.cn/images/z19_return_m.png	0.0 ms	3.0 KiB
www.cas.cn/images/z19_jl_bg_m.jpg	0.0 ms	2.6 KiB
www.cas.cn/images/z19_scroll_wx.png	0.0 ms	2.6 KiB
www.cas.cn/images/blue.png	0.0 ms	2.5 KiB
www.cas.cn/images/z19_search_m.png	0.0 ms	2.4 KiB
www.cas.cn/images/z19_yw_2025tab_m2.png	0.0 ms	2.3 KiB
www.cas.cn/images/z19_index_yw1.png	0.0 ms	2.2 KiB
www.cas.cn/images/z19_pc_m.png	0.0 ms	2.2 KiB
www.cas.cn/images/z19_index_xk1.png	0.0 ms	2.0 KiB
www.cas.cn/images/z19_h5.js	0.0 ms	2.0 KiB
www.cas.cn/images/z19_video_play.png	0.0 ms	1.9 KiB
www.cas.cn/images/z19_en_m.png	0.0 ms	1.7 KiB
www.cas.cn/images/z19_index_tz2.png	0.0 ms	1.7 KiB
www.cas.cn/images/z19_news_list_m.png	0.0 ms	1.6 KiB
www.cas.cn/images/foot_jgawb.png	0.0 ms	1.6 KiB
www.cas.cn/images/z19_index_tj.png	0.0 ms	1.6 KiB
www.cas.cn/images/z19_nav_up.png	0.0 ms	1.4 KiB
www.cas.cn/images/z19_index_xk2.png	0.0 ms	1.4 KiB
www.cas.cn/lib/js/plugin/topSide.min.js	0.0 ms	1.4 KiB
www.cas.cn/images/z19_xk_list_m.png	0.0 ms	1.3 KiB
www.cas.cn/images/z19_resize.js	0.0 ms	1.3 KiB
www.cas.cn/images/z19_index_tz1.png	0.0 ms	1.2 KiB
www.cas.cn/images/z19_bg_blue2.png	0.0 ms	1.2 KiB
www.cas.cn/images/z19_index_ky1.png	0.0 ms	1.2 KiB
www.cas.cn/images/z19_scroll_top.png	0.0 ms	1.1 KiB
www.cas.cn/images/z19_index_ft1.png	0.0 ms	1.0 KiB
www.cas.cn/images/z19_index_video1.png	0.0 ms	1.0 KiB
www.cas.cn/images/z19_index_video2.png	0.0 ms	1020 B
www.cas.cn/images/z19_jl_img.png	0.0 ms	919 B
www.cas.cn/images/z19_index_zt1.png	0.0 ms	877 B
www.cas.cn/images/z19_index_ky2.png	0.0 ms	750 B
www.cas.cn/images/z19_index_ft2.png	0.0 ms	750 B
www.cas.cn/images/z19_index_gz2.png	0.0 ms	727 B
www.cas.cn/images/z19_index_gz1.png	0.0 ms	689 B
www.cas.cn/images/z19_xk_tab_m.png	0.0 ms	665 B
www.cas.cn/images/z19_bg_blue.png	0.0 ms	539 B

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Resource Size	Est Savings
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`	www.cas.cn/gd/202603/W020260320373519199299_ORIGIN.jpg	387.7 KiB	332.1 KiB
div.tab_con > div.ky_img > a > img.hvr-grow `div.tab_con > div.ky_img > a > img.hvr-grow`	www.cas.cn/sygz/202604/W020260416563069960778.png	267.5 KiB	237.6 KiB
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`	www.cas.cn/gd/202603/W020260304562615738276_ORIGIN.jpg	266.6 KiB	210.9 KiB
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`	www.cas.cn/gd/202603/W020260305339535231140_ORIGIN.jpg	233.4 KiB	177.8 KiB
div.video_right > div.video_img > a > img `div.video_right > div.video_img > a > img`	www.cas.cn/spx/202604/W020260417530461254188_ORIGIN.jpg	206.1 KiB	170.8 KiB
div.tab_con > div.video_left > a > img `div.tab_con > div.video_left > a > img`	www.cas.cn/spx/202604/W020260420379180266731_ORIGIN.jpg	216.8 KiB	163.3 KiB
div.tab_con > div.yw_img > a > img.hvr-grow `div.tab_con > div.yw_img > a > img.hvr-grow`	www.cas.cn/yw/202604/W020260414668107692283_ORIGIN.jpg	192.7 KiB	162.8 KiB
div.tab_con > div.ky_img > a > img.hvr-grow `div.tab_con > div.ky_img > a > img.hvr-grow`	www.cas.cn/syky/202604/W020260421315832007785_ORIGIN.jpg	141.6 KiB	111.7 KiB
div.swiper-wrapper > div.swiper-slide > a > img `div.swiper-wrapper > div.swiper-slide > a > img`	www.cas.cn/zt1/202604/W020260401410085460301.jpg	94.6 KiB	82.1 KiB
div.video_right > div.video_img > a > img `div.video_right > div.video_img > a > img`	www.cas.cn/spx/202604/W020260418314827276324_ORIGIN.jpg	114.8 KiB	79.5 KiB
div.swiper-wrapper > div.swiper-slide > a > img `div.swiper-wrapper > div.swiper-slide > a > img`	www.cas.cn/zt1/202603/W020260320378579484579.jpg	88.1 KiB	75.5 KiB
div.swiper-wrapper > div.swiper-slide > a > img `div.swiper-wrapper > div.swiper-slide > a > img`	www.cas.cn/zt1/202604/W020260401410081532588.jpg	82.2 KiB	69.7 KiB
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`	www.cas.cn/gd/202601/W020260121572218060263_ORIGIN.jpg	121.0 KiB	65.4 KiB
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`	www.cas.cn/gd/202603/W020260303457407615596_ORIGIN.jpg	119.8 KiB	64.2 KiB
ul.videoBox > li.hvr-grow-img > a > img.zj_mobblock `ul.videoBox > li.hvr-grow-img > a > img.zj_mobblock`	www.cas.cn/images/zjzkymob_202303.jpg	86.2 KiB	62.7 KiB
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`	www.cas.cn/gd/202601/W020260128305083857947_ORIGIN.jpg	118.2 KiB	62.5 KiB
ul.videoBox > li.hvr-grow-img > a > img.zj_mobblock `ul.videoBox > li.hvr-grow-img > a > img.zj_mobblock`	www.cas.cn/images/zjxbmob_202303.jpg	70.4 KiB	46.9 KiB
div.clearfix > div.videopad > a > img `div.clearfix > div.videopad > a > img`	www.cas.cn/syzc/202312/W020231229530488598921_ORIGIN.jpg	56.1 KiB	26.4 KiB
div.top2 > div.container > a.xsdlogotop > img.logo `div.top2 > div.container > a.xsdlogotop > img.logo`	www.cas.cn/images/z19_logo.png	16.0 KiB	12.4 KiB
ul.videoBox > li.videopad > a > img `ul.videoBox > li.videopad > a > img`	www.cas.cn/images/zkyzsmob_202303.jpg	38.6 KiB	6.6 KiB

Each subpart has specific improvement strategies. Ideally, most of the LCP time should be spent on loading the resources, not within delays.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:label label:Subpart valueType:text] map[key:duration label:Duration valueType:ms]]

items: [map[duration:2257.736 label:Time to first byte subpart:timeToFirstByte] map[duration:275.692 label:Resource load delay subpart:resourceLoadDelay] map[duration:3318.44 label:Resource load duration subpart:resourceLoadDuration] map[duration:33.04 label:Element render delay subpart:elementRenderDelay]]

lhId: page-20-IMG

nodeLabel: ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m

path: 1,HTML,1,BODY,14,DIV,2,DIV,0,DIV,0,UL,1,LI,1,A,0,IMG

selector: ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m

snippet: <img src="./gd/202603/W020260304562615738276_ORIGIN.jpg" class="focus_img_m">

Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading

Why this matters

Performance issues directly impact user engagement and conversion rates.

lhId: page-20-IMG

nodeLabel: ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m

path: 1,HTML,1,BODY,14,DIV,2,DIV,0,DIV,0,UL,1,LI,1,A,0,IMG

selector: ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m

snippet: <img src="./gd/202603/W020260304562615738276_ORIGIN.jpg" class="focus_img_m">

HTTP/2 and HTTP/3 offer many benefits over HTTP/1.1, such as multiplexing. Learn more about using modern HTTP.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Protocol
www.cas.cn/	http/1.1
www.cas.cn/lib/js/plugin/swiper/swiper.min.css	http/1.1
www.cas.cn/lib/css/hover.css	http/1.1
www.cas.cn/images/z19_public.css?v=20251218	http/1.1
www.cas.cn/images/z19_index.css?v=20251225	http/1.1
www.cas.cn/images/z19_styleMobile.css?v=1.0	http/1.1
www.cas.cn/images/z19_logo.png	http/1.1
www.cas.cn/images/dsb01_20251217.png	http/1.1
www.cas.cn/images/dsb02_20251217.png	http/1.1
www.cas.cn/images/z19_pc_m.png	http/1.1
www.cas.cn/images/z19_en_m.png	http/1.1
www.cas.cn/images/wza_2024.png	http/1.1
www.cas.cn/images/z19_search_m.png	http/1.1
www.cas.cn/images/z19_close.png	http/1.1
www.cas.cn/zz/yld/201803/W020191125383560116474.jpg	http/1.1
www.cas.cn/zz/yld/202404/W020240407367171999355_ORIGIN.jpg	http/1.1
www.cas.cn/zz/yld/201704/W020190929738332637068.jpg	http/1.1
www.cas.cn/zz/yld/201909/W020201118270525579945.jpg	http/1.1
www.cas.cn/zz/yld/201605/W020190929739561066807.jpg	http/1.1
www.cas.cn/zz/yld/202308/W020240329553856002424_ORIGIN.jpg	http/1.1
www.cas.cn/zz/yld/202409/W020240912524118761361_ORIGIN.jpg	http/1.1
www.cas.cn/zz/yld/202311/W020231122659760924736.jpg	http/1.1
www.cas.cn/zz/yld/202504/W020250406365313605807_ORIGIN.jpg	http/1.1
www.cas.cn/zz/yld/202504/W020250406366075798999_ORIGIN.jpg	http/1.1
www.cas.cn/zz/yld/202504/W020250416559005659783_ORIGIN.jpg	http/1.1
www.cas.cn/kxyj/202512/W020251218541107090958_ORIGIN.jpg	http/1.1
www.cas.cn/kxyj/202512/W020251218633030399800.jpg	http/1.1
www.cas.cn/images/z19_kxyj_img2.jpg	http/1.1
www.cas.cn/images/20260309_navkjqk.png	http/1.1
www.cas.cn/images/20220826kejitop.jpg	http/1.1
www.cas.cn/cg/112072/images/P020190929620050824644.jpg	http/1.1
www.cas.cn/images/z19_stylePad.css	http/1.1
www.cas.cn/images/z19_school1.jpg	http/1.1
www.cas.cn/images/z19_school2.jpg	http/1.1
www.cas.cn/images/z19_school3.jpg	http/1.1
www.cas.cn/images/z19_school_bar1.jpg	http/1.1
www.cas.cn/images/z19_school_bar2.jpg	http/1.1
www.cas.cn/images/z19_school_bar3.jpg	http/1.1
www.cas.cn/kx/202404/W020240510574946875857_ORIGIN.jpg	http/1.1
www.cas.cn/kx/202404/W020240510575174145626_ORIGIN.jpg	http/1.1
www.cas.cn/images/z2025_dqgz1.jpg	http/1.1
www.cas.cn/images/z19_dqgz2.jpg	http/1.1
www.cas.cn/gd/202603/W020260304562615519478_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202603/W020260304562615738276_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202603/W020260320367237873144_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202603/W020260320373519199299_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202603/W020260303457407403045_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202603/W020260303457407615596_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202603/W020260305339535003381_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202603/W020260305339535231140_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202601/W020260128305083603703_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202601/W020260128305083857947_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202601/W020260121576547305038_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202601/W020260121572218060263_ORIGIN.jpg	http/1.1
www.cas.cn/syzc/202312/W020231229530488598921_ORIGIN.jpg	http/1.1
www.cas.cn/images/z19_index_yw1.png	http/1.1
www.cas.cn/images/z19_index_yw2.png	http/1.1
www.cas.cn/gj/202604/W020260421522038092312.png	http/1.1
www.cas.cn/yw/202604/W020260414668107692283_ORIGIN.jpg	http/1.1
www.cas.cn/images/z19_index_ky1.png	http/1.1
www.cas.cn/images/z19_index_ky2.png	http/1.1
www.cas.cn/syky/202604/W020260421315832007785_ORIGIN.jpg	http/1.1
www.cas.cn/cm/202604/W020260421385309959198.png	http/1.1
www.cas.cn/images/z19_index_gz1.png	http/1.1
www.cas.cn/images/z19_index_gz2.png	http/1.1
www.cas.cn/sygz/202604/W020260416563069960778.png	http/1.1
www.cas.cn/yx/202603/W020260324417741201243.png	http/1.1
www.cas.cn/images/z19_index_zt1.png	http/1.1
www.cas.cn/zt1/202604/W020260401410085460301.jpg	http/1.1
www.cas.cn/zt1/202604/W020260401410081532588.jpg	http/1.1
www.cas.cn/zt1/202603/W020260320378579484579.jpg	http/1.1
www.cas.cn/images/z19_jl_img.png	http/1.1
www.cas.cn/images/zjzkypc_202303.jpg	http/1.1
www.cas.cn/images/zjzkymob_202303.jpg	http/1.1
www.cas.cn/images/zjxbpc_202303.jpg	http/1.1
www.cas.cn/images/zjxbmob_202303.jpg	http/1.1
www.cas.cn/images/zkyzsmob_202303.jpg	http/1.1
www.cas.cn/images/z19_index_tz1.png	http/1.1
www.cas.cn/images/z19_index_tz2.png	http/1.1
www.cas.cn/images/z19_index_video1.png	http/1.1
www.cas.cn/images/z19_index_video2.png	http/1.1
www.cas.cn/spx/202604/W020260420379180266731_ORIGIN.jpg	http/1.1
www.cas.cn/images/z19_video_play.png	http/1.1
www.cas.cn/spx/202604/W020260418314827276324_ORIGIN.jpg	http/1.1
www.cas.cn/spx/202604/W020260417530461254188_ORIGIN.jpg	http/1.1
www.cas.cn/newmedia/dsp/202604/W020260421276040437486.jpg	http/1.1
www.cas.cn/newmedia/dsp/202604/W020260420329652831168.png	http/1.1
www.cas.cn/newmedia/dsp/202604/W020260421546988627746.png	http/1.1
www.cas.cn/images/z19_index_xk2.png	http/1.1
www.cas.cn/images/z19_index_xk1.png	http/1.1
www.cas.cn/images/z19_index_ft1.png	http/1.1
www.cas.cn/images/z19_index_ft2.png	http/1.1
www.cas.cn/images/20230731zcjd.jpg	http/1.1
www.cas.cn/images/swiper.min.js	http/1.1
www.cas.cn/images/z19_jl_icon2.png	http/1.1
www.cas.cn/images/z19_jl_icon4.png	http/1.1
www.cas.cn/images/z19_jl_icon5.png	http/1.1
www.cas.cn/images/z22_jl_xfqd.png	http/1.1
www.cas.cn/images/z19_index_tj.png	http/1.1
www.cas.cn/images/z19_tj_img3.jpg	http/1.1
www.cas.cn/images/z19_tj_img1.jpg	http/1.1
www.cas.cn/images/yjzxgl_202203826.jpg	http/1.1
www.cas.cn/images/z19_scroll_wb.png	http/1.1
www.cas.cn/images/z19_scroll_wx.png	http/1.1
www.cas.cn/images/z19_ewm3.jpg	http/1.1
www.cas.cn/images/z19_scroll_top.png	http/1.1
www.cas.cn/images/z19_return_m.png	http/1.1
www.cas.cn/images/foot_jgawb.png	http/1.1
www.cas.cn/images/jiucuo.png	http/1.1
www.cas.cn/images/blue.png	http/1.1
www.cas.cn/images/z19_gopc.png	http/1.1
www.cas.cn/lib/js/jquery.min.js	http/1.1
www.cas.cn/images/z19_h5.js	http/1.1
www.cas.cn/lib/js/plugin/swiper/idangerous.swiper.min.js	http/1.1
www.cas.cn/lib/js/plugin/jquery.cookie.js	http/1.1
www.cas.cn/images/z19_main.js?v=1.0	http/1.1
www.cas.cn/images/z19_resize.js	http/1.1
www.cas.cn/lib/js/plugin/wza/esdtoolsinit.js	http/1.1
www.cas.cn/lib/js/plugin/topSide.min.js	http/1.1
www.cas.cn/images/z19_nav_up.png	http/1.1
www.cas.cn/images/z19_yw_2025tab_m2.png	http/1.1
www.cas.cn/images/z19_news_list_m.png	http/1.1
www.cas.cn/images/z19_xk_list_m.png	http/1.1
www.cas.cn/images/z19_bg_blue.png	http/1.1
www.cas.cn/images/z19_xk_tab_m.png	http/1.1
www.cas.cn/images/z19_bg_blue2.png	http/1.1
www.cas.cn/images/z19_jl_bg_m.jpg	http/1.1
www.cas.cn/images/z19_foot_m.jpg	http/1.1
www.cas.cn/lib/images/favicon.ico	http/1.1

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Why this matters

Performance issues directly impact user engagement and conversion rates.

description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.

title: Preconnected origins

value: no origins were preconnected

description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.

title: Preconnect candidates

value: No additional origins are good candidates for preconnecting

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size	Duration
www.cas.cn/lib/css/hover.css	116.2 KiB	1.7 s
www.cas.cn/images/z19_styleMobile.css?v=1.0	26.9 KiB	1.1 s
www.cas.cn/images/z19_index.css?v=20251225	13.2 KiB	752 ms
www.cas.cn/images/z19_public.css?v=20251218	24.6 KiB	1.1 s
www.cas.cn/lib/js/plugin/swiper/swiper.min.css	19.5 KiB	602 ms

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 1.4 s

URL	Time Spent
cas.cn/	773 ms
www.cas.cn/	630 ms
www.cas.cn/	0.0 ms

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

Diagnostics

Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 150 ms 23.9 KiB

URL	Transfer Size	Est Savings
www.cas.cn/lib/css/hover.css	116.2 KiB	18.8 KiB
www.cas.cn/images/z19_public.css?v=20251218	24.6 KiB	3.0 KiB
www.cas.cn/images/z19_styleMobile.css?v=1.0	26.9 KiB	2.1 KiB

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 900 ms 183.4 KiB

URL	Transfer Size	Est Savings
www.cas.cn/lib/css/hover.css	116.0 KiB	115.7 KiB
www.cas.cn/images/z19_public.css?v=20251218	24.4 KiB	19.2 KiB
www.cas.cn/images/z19_styleMobile.css?v=1.0	26.7 KiB	19.2 KiB
www.cas.cn/lib/js/plugin/swiper/swiper.min.css	19.3 KiB	17.5 KiB
www.cas.cn/images/z19_stylePad.css	11.9 KiB	11.9 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Why this matters

Multi-megabyte JavaScript bundles delay every interactive feature on the page.

Learn more ▾

This is the Lighthouse audit fired when too much JS is shipped relative to what executes. The fix isn't a config flag — it requires bundle analysis (webpack-bundle-analyzer, rollup-plugin-visualizer), splitting routes into chunks, lazy-loading off-screen components, and removing unused dependencies. Fundamentally different from minification: minifying reduces byte count, this reduces what's downloaded at all.

Source: Google web.dev / Lighthouse

Estimated savings: 600 ms 110.5 KiB

URL	Transfer Size	Est Savings
www.cas.cn/images/swiper.min.js	94.2 KiB	59.9 KiB
www.cas.cn/lib/js/jquery.min.js	94.9 KiB	50.7 KiB

Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 0.0 ms 2.5 KiB

URL	Transfer Size	Est Savings
www.cas.cn/images/z19_main.js?v=1.0	12.8 KiB	2.5 KiB

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size
www.cas.cn/gd/202603/W020260320367237873144_ORIGIN.jpg	622.6 KiB
www.cas.cn/gd/202603/W020260304562615519478_ORIGIN.jpg	456.8 KiB
www.cas.cn/yx/202603/W020260324417741201243.png	454.2 KiB
www.cas.cn/gd/202603/W020260320373519199299_ORIGIN.jpg	387.9 KiB
www.cas.cn/gd/202603/W020260305339535003381_ORIGIN.jpg	366.7 KiB
www.cas.cn/gj/202604/W020260421522038092312.png	350.4 KiB
www.cas.cn/cm/202604/W020260421385309959198.png	280.4 KiB
www.cas.cn/newmedia/dsp/202604/W020260420329652831168.png	269.6 KiB
www.cas.cn/sygz/202604/W020260416563069960778.png	267.7 KiB
www.cas.cn/gd/202603/W020260304562615738276_ORIGIN.jpg	266.8 KiB

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work

Why this matters

Performance issues directly impact user engagement and conversion rates.

Category	Time Spent
Other	1.8 s
Style & Layout	282 ms
Rendering	218 ms
Script Evaluation	209 ms
Parse HTML & CSS	51 ms
Script Parsing & Compilation	35 ms

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`	www.cas.cn/images/z19_tj_img3.jpg
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`	www.cas.cn/images/z19_tj_img1.jpg
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`	www.cas.cn/images/yjzxgl_202203826.jpg
div.top2 > div.container > a.xsdlogotop > img.logo `div.top2 > div.container > a.xsdlogotop > img.logo`	www.cas.cn/images/z19_logo.png
ul.tab_title > li.tab_title_yw1 > a > img `ul.tab_title > li.tab_title_yw1 > a > img`	www.cas.cn/images/z19_index_yw1.png
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`	www.cas.cn/images/z19_index_yw2.png
ul.jl_list > li.jl_col4 > a > img `ul.jl_list > li.jl_col4 > a > img`	www.cas.cn/images/z19_jl_icon4.png
ul.jl_list > li.jl_col5 > a > img `ul.jl_list > li.jl_col5 > a > img`	www.cas.cn/images/z19_jl_icon5.png
ul.jl_list > li.jl_col7 > a > img `ul.jl_list > li.jl_col7 > a > img`	www.cas.cn/images/z22_jl_xfqd.png
ul.jl_list > li.jl_col2 > a > img `ul.jl_list > li.jl_col2 > a > img`	www.cas.cn/images/z19_jl_icon2.png
li > span#_ideConac > a > img#imgConac `li > span#_ideConac > a > img#imgConac`	www.cas.cn/images/blue.png
li > span#_span_jiucuo > a > img `li > span#_span_jiucuo > a > img`	www.cas.cn/images/jiucuo.png
div.container > div.top_link_m > a#change_pc > img `div.container > div.top_link_m > a#change_pc > img`	www.cas.cn/images/z19_pc_m.png
div.container > div.top_link_m > a > img `div.container > div.top_link_m > a > img`	www.cas.cn/images/z19_en_m.png
div.container > div.top_link_m > a#toolbarSwitchmob > img `div.container > div.top_link_m > a#toolbarSwitchmob > img`	www.cas.cn/images/wza_2024.png
div.container > div.top_link_m > a > img#m_search `div.container > div.top_link_m > a > img#m_search`	www.cas.cn/images/z19_search_m.png
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`	www.cas.cn/images/z19_index_ky1.png
ul.tab_title > li > a > img `ul.tab_title > li > a > img`	www.cas.cn/images/z19_index_ky2.png
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`	www.cas.cn/images/z19_index_gz1.png
ul.tab_title > li > a > img `ul.tab_title > li > a > img`	www.cas.cn/images/z19_index_gz2.png
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`	www.cas.cn/images/z19_index_tz1.png
ul.tab_title > li > a > img `ul.tab_title > li > a > img`	www.cas.cn/images/z19_index_tz2.png
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`	www.cas.cn/images/z19_index_video1.png
ul.tab_title > li > a > img `ul.tab_title > li > a > img`	www.cas.cn/images/z19_index_video2.png
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`	www.cas.cn/images/z19_index_xk2.png
ul.tab_title > li > a > img `ul.tab_title > li > a > img`	www.cas.cn/images/z19_index_xk1.png
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`	www.cas.cn/images/z19_index_ft1.png
ul.tab_title > li > a > img `ul.tab_title > li > a > img`	www.cas.cn/images/z19_index_ft2.png
div.divBox > div.div_title > p > img `div.divBox > div.div_title > p > img`	www.cas.cn/images/z19_index_zt1.png
div.divBox > div.jl > div.jl_left > img `div.divBox > div.jl > div.jl_left > img`	www.cas.cn/images/z19_jl_img.png
div.tj > div.div_title > p > img `div.tj > div.div_title > p > img`	www.cas.cn/images/z19_index_tj.png
div.boxcenter > div.foot_txt > p > img `div.boxcenter > div.foot_txt > p > img`	www.cas.cn/images/foot_jgawb.png

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Layout shift culprits

●Optimize DOM size

●Font display

●Forced reflow

●Optimize viewport for mobile

●Max Potential First Input Delay 40 ms

●JavaScript execution time 0.2 s

●Avoid long main-thread tasks 1 long task found

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 280 ms

●Server Backend Latencies 0 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Initial server response time was short Root document took 280 ms

●Avoid large layout shifts 3 layout shifts found

○INP breakdown

○User Timing marks and measures

○Avoid non-composited animations

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
2026年04月14日 `div.yw_img > h5 > div.date > span`
2026年02月11日 `div.tab_con > ul.tzgg > li > p`
2026年04月20日 `div.tab_con > ul.tzgg > li > p`

These are opportunities to improve the legibility of your content.

Internationalization and localization

If a page doesn't specify a `lang` attribute, a screen reader assumes that the page is in the default language that the user chose when setting up the screen reader. If the page isn't actually in the default language, then the screen reader might not announce the page's text correctly. Learn more about the `lang` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
html `html`

These are opportunities to improve the interpretation of your content by users in different locales.

Names and labels

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.top2 > div.container > a.xsdlogotop > img.logo `div.top2 > div.container > a.xsdlogotop > img.logo`
div.container > div.top_link_m > a#change_pc > img `div.container > div.top_link_m > a#change_pc > img`
div.container > div.top_link_m > a > img `div.container > div.top_link_m > a > img`
div.container > div.top_link_m > a#toolbarSwitchmob > img `div.container > div.top_link_m > a#toolbarSwitchmob > img`
div.container > div.top_link_m > a > img#m_search `div.container > div.top_link_m > a > img#m_search`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
div.clearfix > div.videopad > a > img `div.clearfix > div.videopad > a > img`
ul.tab_title > li.tab_title_yw1 > a > img `ul.tab_title > li.tab_title_yw1 > a > img`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
div.tab_con > div.yw_img > a > img.hvr-grow `div.tab_con > div.yw_img > a > img.hvr-grow`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.tab_con > div.ky_img > a > img.hvr-grow `div.tab_con > div.ky_img > a > img.hvr-grow`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.tab_con > div.ky_img > a > img.hvr-grow `div.tab_con > div.ky_img > a > img.hvr-grow`
ul.videoBox > li.hvr-grow-img > a > img.zj_mobblock `ul.videoBox > li.hvr-grow-img > a > img.zj_mobblock`
ul.videoBox > li.hvr-grow-img > a > img.zj_mobblock `ul.videoBox > li.hvr-grow-img > a > img.zj_mobblock`
ul.videoBox > li.videopad > a > img `ul.videoBox > li.videopad > a > img`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.tab_con > div.video_left > a > img `div.tab_con > div.video_left > a > img`
div.tab_con > div.video_left > a > img.video_play2 `div.tab_con > div.video_left > a > img.video_play2`
div.video_right > div.video_img > a > img `div.video_right > div.video_img > a > img`
div.video_right > div.video_img > a > img.video_play2 `div.video_right > div.video_img > a > img.video_play2`
div.video_right > div.video_img > a > img `div.video_right > div.video_img > a > img`
div.video_right > div.video_img > a > img.video_play2 `div.video_right > div.video_img > a > img.video_play2`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.divBox > div.div_title > p > img `div.divBox > div.div_title > p > img`
div.swiper-wrapper > div.swiper-slide > a > img `div.swiper-wrapper > div.swiper-slide > a > img`
div.swiper-wrapper > div.swiper-slide > a > img `div.swiper-wrapper > div.swiper-slide > a > img`
div.swiper-wrapper > div.swiper-slide > a > img `div.swiper-wrapper > div.swiper-slide > a > img`
div.divBox > div.jl > div.jl_left > img `div.divBox > div.jl > div.jl_left > img`
ul.jl_list > li.jl_col2 > a > img `ul.jl_list > li.jl_col2 > a > img`
ul.jl_list > li.jl_col4 > a > img `ul.jl_list > li.jl_col4 > a > img`
ul.jl_list > li.jl_col5 > a > img `ul.jl_list > li.jl_col5 > a > img`
ul.jl_list > li.jl_col7 > a > img `ul.jl_list > li.jl_col7 > a > img`
div.tj > div.div_title > p > img `div.tj > div.div_title > p > img`
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`
div.boxcenter > div.foot_txt > p > img `div.boxcenter > div.foot_txt > p > img`
li > span#_span_jiucuo > a > img `li > span#_span_jiucuo > a > img`
li > span#_ideConac > a > img#imgConac `li > span#_ideConac > a > img#imgConac`

Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn how to make links accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
body > div.top2 > div.container > a.xsdlogotop `body > div.top2 > div.container > a.xsdlogotop`
div.top2 > div.container > div.top_link_m > a#change_pc `div.top2 > div.container > div.top_link_m > a#change_pc`
div.top2 > div.container > div.top_link_m > a `div.top2 > div.container > div.top_link_m > a`
div.top2 > div.container > div.top_link_m > a#toolbarSwitchmob `div.top2 > div.container > div.top_link_m > a#toolbarSwitchmob`
div.top2 > div.container > div.top_link_m > a `div.top2 > div.container > div.top_link_m > a`
div.top2 > div.container > div.top_link_m > a `div.top2 > div.container > div.top_link_m > a`
body > div.container > div.topTitle > a `body > div.container > div.topTitle > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div.container > div.clearfix > div.videopad > a `div.container > div.clearfix > div.videopad > a`
div#m_swiper_zt > div.swiper-wrapper > div.swiper-slide > a `div#m_swiper_zt > div.swiper-wrapper > div.swiper-slide > a`
div#m_swiper_zt > div.swiper-wrapper > div.swiper-slide > a `div#m_swiper_zt > div.swiper-wrapper > div.swiper-slide > a`
div#m_swiper_zt > div.swiper-wrapper > div.swiper-slide > a `div#m_swiper_zt > div.swiper-wrapper > div.swiper-slide > a`
div.foot_img > li > span#_span_jiucuo > a `div.foot_img > li > span#_span_jiucuo > a`
div.foot_img > li > span#_ideConac > a `div.foot_img > li > span#_ideConac > a`

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Tables and lists

Screen readers have a specific way of announcing lists. Ensuring proper list structure aids screen reader output. Learn more about proper list structure.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
李昕欣：传感器研究从应用中来，到应用中去徐新文：沙漠里编织“绿丝带” 包云岗：“科研重工业模式”践行者科技为犁，耕护黑土粮仓更多学者风采 + `div.divBox3 > div.tabBox > div.tab_con > ul.xk_list`
蔡长塔\| 传承践行正确政绩观勇担抢占科技制高点时代使命王赤\| 树立和践行正确政绩观，以实干实绩加快抢占空间科技制高点向华\| 以高水平科技自立自… `div.divBox3 > div.tabBox > div.tab_con > ul.tzgg`

Screen readers require list items (`<li>`) to be contained within a parent `<ul>`, `<ol>` or `<menu>` to be announced properly. Learn more about proper list structure.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.foot > div.boxcenter > div.foot_img > li `div.foot > div.boxcenter > div.foot_img > li`
div.foot > div.boxcenter > div.foot_img > li `div.foot > div.boxcenter > div.foot_img > li`

These are opportunities to improve the experience of reading tabular or list data using assistive technology, like a screen reader.

Best practices

Disabling zooming is problematic for users with low vision who rely on screen magnification to properly see the contents of a web page. Learn more about the viewport meta tag.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
head > meta `head > meta`
body > meta `body > meta`

One main landmark helps screen reader users navigate a web page. Learn more about landmarks.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
html `html`

These items highlight common accessibility best practices.

Navigation

A value greater than 0 implies an explicit navigation ordering. Although technically valid, this often creates frustrating experiences for users who rely on assistive technologies. Learn more about the `tabindex` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
按回车键在新窗口打开无障碍说明页面,按Ctrl+~键打开导盲模式。 `body > a#esdTipLink1`

These are opportunities to improve keyboard navigation in your application.

○Interactive controls are keyboard focusable

○Interactive elements indicate their purpose and state

○The page has a logical tab order

○Visual order on the page follows DOM order

○User focus is not accidentally trapped in a region

○The user's focus is directed to new content added to the page

○HTML5 landmark elements are used to improve navigation

○Offscreen content is hidden from assistive technology

○Custom controls have associated labels

○Custom controls have ARIA roles

●`[aria-*]` attributes match their roles

●`[aria-hidden="true"]` is not present on the document `<body>`

●`[aria-*]` attributes have valid values

●`[aria-*]` attributes are valid and not misspelled

●ARIA attributes are used as specified for the element's role

●Elements use only permitted ARIA attributes

●Document has a `<title>` element

●Links are distinguishable without relying on color.

●Touch targets have sufficient size and spacing.

●Heading elements appear in a sequentially-descending order

○`[accesskey]` values are unique

○`button`, `link`, and `menuitem` elements have accessible names

○Deprecated ARIA roles were not used

○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.

○`[aria-hidden="true"]` elements do not contain focusable descendents

○ARIA input fields have accessible names

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○`[role]`s have all required `[aria-*]` attributes

○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.

○`[role]`s are contained by their required parent element

○`[role]` values are valid

○Elements with the `role=text` attribute do not have focusable descendents.

○ARIA toggle fields have accessible names

○ARIA `tooltip` elements have accessible names

○ARIA `treeitem` elements have accessible names

○Buttons have an accessible name

○The page contains a heading, skip link, or landmark region

○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.

○Definition list items are wrapped in `<dl>` elements

○ARIA IDs are unique

○No form fields have multiple labels

○`<frame>` or `<iframe>` elements have a title

○`<html>` element has a valid value for its `[lang]` attribute

○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.

○Input buttons have discernible text.

○`<input type="image">` elements have `[alt]` text

○Form elements have associated labels

○The document does not use `<meta http-equiv="refresh">`

○`<object>` elements have alternate text

○Select elements have associated label elements.

○Skip links are focusable.

○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.

○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.

○`[lang]` attributes have a valid value

○`<video>` elements contain a `<track>` element with `[kind="captions"]`

○Tables have different content in the summary attribute and `<caption>`.

○All heading elements contain content.

○Uses ARIA roles only on compatible elements

○Image elements do not have `[alt]` attributes that are redundant text.

○Identical links have the same purpose.

○Elements with visible text labels have matching accessible names.

○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.

○`<td>` elements in a large `<table>` have one or more table headers.

Best Practices

Trust and Safety

All sites should be protected with HTTPS, even ones that don't handle sensitive data. This includes avoiding mixed content, where some resources are loaded over HTTP despite the initial request being served over HTTPS. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs. Learn more about HTTPS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Insecure URL	Request Resolution
www.cas.cn/	Allowed

User Experience

Image display dimensions should match natural aspect ratio. Learn more about image aspect ratio.

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Aspect Ratio (Displayed)	Aspect Ratio (Actual)
div.video_right > div.video_img > a > img `div.video_right > div.video_img > a > img`	www.cas.cn/spx/202604/W020260418314827276324_ORIGIN.jpg	328 x 216 (1.52)	702 x 468 (1.50)
div.video_right > div.video_img > a > img `div.video_right > div.video_img > a > img`	www.cas.cn/spx/202604/W020260417530461254188_ORIGIN.jpg	328 x 216 (1.52)	702 x 468 (1.50)
ul.tzgg > li > a > img `ul.tzgg > li > a > img`	www.cas.cn/images/20230731zcjd.jpg	100 x 200 (0.50)	700 x 200 (3.50)
div.model_box > div.model_top > a > img `div.model_box > div.model_top > a > img`	www.cas.cn/cg/112072/images/P020190929620050824644.jpg	100 x 85 (1.18)	1220 x 85 (14.35)

Image natural dimensions should be proportional to the display size and the pixel ratio to maximize image clarity. Learn how to provide responsive images.

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Displayed size	Actual size	Expected size
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`	www.cas.cn/gd/202603/W020260303457407615596_ORIGIN.jpg	750 x 456	750 x 456	1125 x 684
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`	www.cas.cn/gd/202603/W020260305339535231140_ORIGIN.jpg	750 x 456	750 x 456	1125 x 684
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`	www.cas.cn/gd/202603/W020260320373519199299_ORIGIN.jpg	750 x 456	750 x 456	1125 x 684
div.clearfix > div.videopad > a > img `div.clearfix > div.videopad > a > img`	www.cas.cn/syzc/202312/W020231229530488598921_ORIGIN.jpg	750 x 217	794 x 230	1125 x 326
div.top2 > div.container > a.xsdlogotop > img.logo `div.top2 > div.container > a.xsdlogotop > img.logo`	www.cas.cn/images/z19_logo.png	310 x 72	310 x 72	465 x 108
div.container > div.top_link_m > a#toolbarSwitchmob > img `div.container > div.top_link_m > a#toolbarSwitchmob > img`	www.cas.cn/images/wza_2024.png	72 x 72	76 x 76	108 x 108
div.container > div.top_link_m > a > img `div.container > div.top_link_m > a > img`	www.cas.cn/images/z19_en_m.png	72 x 72	76 x 76	108 x 108
div.container > div.top_link_m > a#change_pc > img `div.container > div.top_link_m > a#change_pc > img`	www.cas.cn/images/z19_pc_m.png	72 x 72	76 x 76	108 x 108
div.container > div.top_link_m > a > img#m_search `div.container > div.top_link_m > a > img#m_search`	www.cas.cn/images/z19_search_m.png	72 x 72	76 x 76	108 x 108

General

Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Deprecation / Warning	Source
Specifying overflow: visible on img, video and canvas tags may cause them to produce visual content outside of the element bounds. See https://github.com/WICG/shared-element-transitions/blob/main/debugging_overflow_on_images.md.	www.cas.cn/

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

Why this matters

Performance issues directly impact user engagement and conversion rates.

Source	Description
www.cas.cn/lib/js/plugin/wza/esdtoolsinit.js line 1321, col 17	`TypeError: EsdToolbarInit.openCountFunc is not a function at EsdToolbarInit.openFunc_mobile (https://www.cas.cn/lib/js/plugin/wza/esdtoolsinit.js:1322:18) at EsdToolbarInit.init (https://www.cas.cn/lib/js/plugin/wza/esdtoolsinit.js:166:20) at https://www.cas.cn/lib/js/plugin/wza/esdtoolsinit.js:1425:17`

●Avoids third-party cookies

●Allows users to paste into input fields

●Avoids requesting the geolocation permission on page load

●Avoids requesting the notification permission on page load

●Page has the HTML doctype

●Properly defines charset

●No issues in the `Issues` panel in Chrome Devtools

●Ensure CSP is effective against XSS attacks

●Use a strong HSTS policy

●Ensure proper origin isolation with COOP

●Mitigate clickjacking with XFO or CSP

●Mitigate DOM-based XSS with Trusted Types

●Detected JavaScript libraries

●Page has valid source maps

○Redirects HTTP traffic to HTTPS

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

Content Best Practices

Meta descriptions may be included in search results to concisely summarize page content. Learn more about the meta description.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.top2 > div.container > a.xsdlogotop > img.logo `div.top2 > div.container > a.xsdlogotop > img.logo`
div.container > div.top_link_m > a#change_pc > img `div.container > div.top_link_m > a#change_pc > img`
div.container > div.top_link_m > a > img `div.container > div.top_link_m > a > img`
div.container > div.top_link_m > a#toolbarSwitchmob > img `div.container > div.top_link_m > a#toolbarSwitchmob > img`
div.container > div.top_link_m > a > img#m_search `div.container > div.top_link_m > a > img#m_search`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`
div.clearfix > div.videopad > a > img `div.clearfix > div.videopad > a > img`
ul.tab_title > li.tab_title_yw1 > a > img `ul.tab_title > li.tab_title_yw1 > a > img`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
div.tab_con > div.yw_img > a > img.hvr-grow `div.tab_con > div.yw_img > a > img.hvr-grow`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.tab_con > div.ky_img > a > img.hvr-grow `div.tab_con > div.ky_img > a > img.hvr-grow`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.tab_con > div.ky_img > a > img.hvr-grow `div.tab_con > div.ky_img > a > img.hvr-grow`
ul.videoBox > li.hvr-grow-img > a > img.zj_mobblock `ul.videoBox > li.hvr-grow-img > a > img.zj_mobblock`
ul.videoBox > li.hvr-grow-img > a > img.zj_mobblock `ul.videoBox > li.hvr-grow-img > a > img.zj_mobblock`
ul.videoBox > li.videopad > a > img `ul.videoBox > li.videopad > a > img`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.tab_con > div.video_left > a > img `div.tab_con > div.video_left > a > img`
div.tab_con > div.video_left > a > img.video_play2 `div.tab_con > div.video_left > a > img.video_play2`
div.video_right > div.video_img > a > img `div.video_right > div.video_img > a > img`
div.video_right > div.video_img > a > img.video_play2 `div.video_right > div.video_img > a > img.video_play2`
div.video_right > div.video_img > a > img `div.video_right > div.video_img > a > img`
div.video_right > div.video_img > a > img.video_play2 `div.video_right > div.video_img > a > img.video_play2`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.divBox > div.div_title > p > img `div.divBox > div.div_title > p > img`
div.swiper-wrapper > div.swiper-slide > a > img `div.swiper-wrapper > div.swiper-slide > a > img`
div.swiper-wrapper > div.swiper-slide > a > img `div.swiper-wrapper > div.swiper-slide > a > img`
div.swiper-wrapper > div.swiper-slide > a > img `div.swiper-wrapper > div.swiper-slide > a > img`
div.divBox > div.jl > div.jl_left > img `div.divBox > div.jl > div.jl_left > img`
ul.jl_list > li.jl_col2 > a > img `ul.jl_list > li.jl_col2 > a > img`
ul.jl_list > li.jl_col4 > a > img `ul.jl_list > li.jl_col4 > a > img`
ul.jl_list > li.jl_col5 > a > img `ul.jl_list > li.jl_col5 > a > img`
ul.jl_list > li.jl_col7 > a > img `ul.jl_list > li.jl_col7 > a > img`
div.tj > div.div_title > p > img `div.tj > div.div_title > p > img`
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`
div.boxcenter > div.foot_txt > p > img `div.boxcenter > div.foot_txt > p > img`
li > span#_span_jiucuo > a > img `li > span#_span_jiucuo > a > img`
li > span#_ideConac > a > img#imgConac `li > span#_ideConac > a > img#imgConac`

Format your HTML in a way that enables crawlers to better understand your app’s content.

Crawling and Indexing

Search engines may use `href` attributes on links to crawl websites. Ensure that the `href` attribute of anchor elements links to an appropriate destination, so more pages of the site can be discovered. Learn how to make links crawlable

Why this matters

Performance issues directly impact user engagement and conversion rates.

Uncrawlable Link
无障碍 `div.container > div.top_r > div.top_link > a#toolbarSwitch`
div.top2 > div.container > div.top_link_m > a#toolbarSwitchmob `div.top2 > div.container > div.top_link_m > a#toolbarSwitchmob`
按回车键在新窗口打开无障碍说明页面,按Ctrl+~键打开导盲模式。 `body > a#esdTipLink1`
配色 `div#toolbar > ul > li > a#toolbar_colorChange`
阅读 `div#toolbar > ul > li > a#toolbar_speakVolume`
设置 `div#toolbar > ul > li > a#toolbar_config`
退出 `div#toolbar > ul > li > a#toolbar_exit`

To appear in search results, crawlers need access to your app.

○Structured data is valid

●Page isn’t blocked from indexing

●Document has a `<title>` element

●Page has successful HTTP status code

●Links have descriptive text

●Document has a valid `hreflang`

○robots.txt is valid

○Document has a valid `rel=canonical`

Lighthouse Scores

Industry-standard audits powered by Google Lighthouse. — Desktop

Performance

Accessibility

Best Practices

SEO

Core Web Vitals

Key metrics that affect user experience. — Desktop

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

890 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

3.44 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

0 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.627

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

7.30 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

3.54 s

Detailed Report

Audit breakdown by category with detailed findings.

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Why this matters

Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.

Learn more ▾

Source: Google web.dev / Lighthouse

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Request	Cache TTL	Transfer Size
www.cas.cn/gd/202603/W020260320367237873144_ORIGIN.jpg	0.0 ms	622.6 KiB
www.cas.cn/gd/202603/W020260304562615519478_ORIGIN.jpg	0.0 ms	456.8 KiB
www.cas.cn/yx/202603/W020260324417741201243.png	0.0 ms	454.2 KiB
www.cas.cn/images/topbgimg_20251217.png	0.0 ms	441.8 KiB
www.cas.cn/gd/202603/W020260320373519199299_ORIGIN.jpg	0.0 ms	387.9 KiB
www.cas.cn/gd/202603/W020260305339535003381_ORIGIN.jpg	0.0 ms	366.7 KiB
www.cas.cn/gj/202604/W020260421522038092312.png	0.0 ms	350.4 KiB
www.cas.cn/cm/202604/W020260421385309959198.png	0.0 ms	280.4 KiB
www.cas.cn/newmedia/dsp/202604/W020260420329652831168.png	0.0 ms	269.6 KiB
www.cas.cn/sygz/202604/W020260416563069960778.png	0.0 ms	267.7 KiB
www.cas.cn/gd/202603/W020260304562615738276_ORIGIN.jpg	0.0 ms	266.8 KiB
www.cas.cn/gd/202603/W020260305339535231140_ORIGIN.jpg	0.0 ms	233.6 KiB
www.cas.cn/gd/202601/W020260128305083603703_ORIGIN.jpg	0.0 ms	230.0 KiB
www.cas.cn/spx/202604/W020260420379180266731_ORIGIN.jpg	0.0 ms	217.0 KiB
www.cas.cn/images/z19_ewm3.jpg	0.0 ms	215.4 KiB
www.cas.cn/gd/202603/W020260303457407403045_ORIGIN.jpg	0.0 ms	212.4 KiB
www.cas.cn/images/z19_foot.png	0.0 ms	208.7 KiB
www.cas.cn/spx/202604/W020260417530461254188_ORIGIN.jpg	0.0 ms	206.3 KiB
www.cas.cn/yw/202604/W020260414668107692283_ORIGIN.jpg	0.0 ms	192.9 KiB
www.cas.cn/images/20260309_navkjqk.png	0.0 ms	187.3 KiB
www.cas.cn/newmedia/dsp/202604/W020260421546988627746.png	0.0 ms	167.1 KiB
www.cas.cn/syky/202604/W020260421315832007785_ORIGIN.jpg	0.0 ms	141.8 KiB
www.cas.cn/images/20230731zcjd.jpg	0.0 ms	129.0 KiB
www.cas.cn/gd/202601/W020260121576547305038_ORIGIN.jpg	0.0 ms	123.3 KiB
www.cas.cn/images/z19_foot_m.jpg	0.0 ms	122.8 KiB
www.cas.cn/gd/202601/W020260121572218060263_ORIGIN.jpg	0.0 ms	121.2 KiB
www.cas.cn/gd/202603/W020260303457407615596_ORIGIN.jpg	0.0 ms	120.0 KiB
www.cas.cn/gd/202601/W020260128305083857947_ORIGIN.jpg	0.0 ms	118.4 KiB
www.cas.cn/lib/css/hover.css	0.0 ms	116.2 KiB
www.cas.cn/spx/202604/W020260418314827276324_ORIGIN.jpg	0.0 ms	115.0 KiB
www.cas.cn/lib/js/plugin/wza/esdtoolsinit.js	0.0 ms	100.9 KiB
www.cas.cn/lib/js/jquery.min.js	0.0 ms	95.1 KiB
www.cas.cn/zt1/202604/W020260401410085460301.jpg	0.0 ms	94.8 KiB
www.cas.cn/images/swiper.min.js	0.0 ms	94.4 KiB
www.cas.cn/zt1/202603/W020260320378579484579.jpg	0.0 ms	88.3 KiB
www.cas.cn/images/zjzkymob_202303.jpg	0.0 ms	86.4 KiB
www.cas.cn/zt1/202604/W020260401410081532588.jpg	0.0 ms	82.5 KiB
www.cas.cn/zz/yld/201605/W020190929739561066807.jpg	0.0 ms	81.1 KiB
www.cas.cn/kxyj/202512/W020251218633030399800.jpg	0.0 ms	75.0 KiB
www.cas.cn/zz/yld/201704/W020190929738332637068.jpg	0.0 ms	73.3 KiB
www.cas.cn/kxyj/202512/W020251218541107090958_ORIGIN.jpg	0.0 ms	71.2 KiB
www.cas.cn/images/zjxbmob_202303.jpg	0.0 ms	70.6 KiB
www.cas.cn/images/z19_kxyj_img2.jpg	0.0 ms	69.7 KiB
www.cas.cn/syzc/202312/W020231229530488598921_ORIGIN.jpg	0.0 ms	56.4 KiB
www.cas.cn/images/z19_tj_img1.jpg	0.0 ms	53.2 KiB
www.cas.cn/zz/yld/201803/W020191125383560116474.jpg	0.0 ms	49.3 KiB
www.cas.cn/images/zjzkypc_202303.jpg	0.0 ms	47.3 KiB
www.cas.cn/lib/js/plugin/swiper/idangerous.swiper.min.js	0.0 ms	44.4 KiB
www.cas.cn/kx/202404/W020240510574946875857_ORIGIN.jpg	0.0 ms	43.9 KiB
www.cas.cn/zz/yld/202504/W020250416559005659783_ORIGIN.jpg	0.0 ms	40.3 KiB
www.cas.cn/images/zkyzsmob_202303.jpg	0.0 ms	38.8 KiB
www.cas.cn/images/z2025_dqgz1.jpg	0.0 ms	37.9 KiB
www.cas.cn/images/z19_dqgz2.jpg	0.0 ms	37.4 KiB
www.cas.cn/images/zkyzspc_202303.jpg	0.0 ms	36.9 KiB
www.cas.cn/zz/yld/202308/W020240329553856002424_ORIGIN.jpg	0.0 ms	36.5 KiB
www.cas.cn/zz/yld/202409/W020240912524118761361_ORIGIN.jpg	0.0 ms	36.2 KiB
www.cas.cn/images/dsb02_20251217.png	0.0 ms	36.0 KiB
www.cas.cn/zz/yld/202404/W020240407367171999355_ORIGIN.jpg	0.0 ms	34.7 KiB
www.cas.cn/images/zjxbpc_202303.jpg	0.0 ms	34.5 KiB
www.cas.cn/zz/yld/202504/W020250406365313605807_ORIGIN.jpg	0.0 ms	34.0 KiB
www.cas.cn/zz/yld/202311/W020231122659760924736.jpg	0.0 ms	33.6 KiB
www.cas.cn/zz/yld/202504/W020250406366075798999_ORIGIN.jpg	0.0 ms	31.3 KiB
www.cas.cn/zz/yld/201909/W020201118270525579945.jpg	0.0 ms	30.5 KiB
www.cas.cn/kx/202404/W020240510575174145626_ORIGIN.jpg	0.0 ms	29.0 KiB
www.cas.cn/images/z19_public.css?v=20251218	0.0 ms	24.6 KiB
www.cas.cn/newmedia/dsp/202604/W020260421276040437486.jpg	0.0 ms	23.5 KiB
www.cas.cn/images/20220826kejitop.jpg	0.0 ms	23.3 KiB
www.cas.cn/cg/112072/images/P020190929620050824644.jpg	0.0 ms	22.8 KiB
www.cas.cn/images/yjzxgl_202203826.jpg	0.0 ms	21.4 KiB
www.cas.cn/lib/js/plugin/swiper/swiper.min.css	0.0 ms	19.5 KiB
www.cas.cn/images/dsb01_20251217.png	0.0 ms	18.2 KiB
www.cas.cn/images/z19_logo.png	0.0 ms	16.3 KiB
www.cas.cn/images/z19_tj_img3.jpg	0.0 ms	15.2 KiB
www.cas.cn/images/z19_school_bar1.jpg	0.0 ms	13.8 KiB
www.cas.cn/images/z19_index.css?v=20251225	0.0 ms	13.2 KiB
www.cas.cn/images/z19_main.js?v=1.0	0.0 ms	13.0 KiB
www.cas.cn/images/z19_school_bar3.jpg	0.0 ms	12.3 KiB
www.cas.cn/images/z19_stylePad.css	0.0 ms	12.1 KiB
www.cas.cn/images/z19_school_bar2.jpg	0.0 ms	11.7 KiB
www.cas.cn/images/z19_school3.jpg	0.0 ms	10.3 KiB
www.cas.cn/images/z19_school2.jpg	0.0 ms	9.5 KiB
www.cas.cn/images/z19_school1.jpg	0.0 ms	8.0 KiB
www.cas.cn/images/z19_close.png	0.0 ms	6.3 KiB
www.cas.cn/images/z22_jl_xfqd.png	0.0 ms	5.3 KiB
www.cas.cn/images/z19_jl_icon4.png	0.0 ms	5.2 KiB
www.cas.cn/images/z19_index_yw2.png	0.0 ms	4.6 KiB
www.cas.cn/images/z19_jl_icon2.png	0.0 ms	4.6 KiB
www.cas.cn/images/z19_gopc.png	0.0 ms	4.4 KiB
www.cas.cn/images/jiucuo.png	0.0 ms	4.1 KiB
www.cas.cn/images/z19_jl_icon5.png	0.0 ms	3.7 KiB
www.cas.cn/images/wza_2024.png	0.0 ms	3.3 KiB
www.cas.cn/lib/js/plugin/jquery.cookie.js	0.0 ms	3.3 KiB
www.cas.cn/images/z19_scroll_wb.png	0.0 ms	3.2 KiB
www.cas.cn/images/z19_return_m.png	0.0 ms	3.0 KiB
www.cas.cn/images/z19_scroll_wx.png	0.0 ms	2.6 KiB
www.cas.cn/images/blue.png	0.0 ms	2.5 KiB
www.cas.cn/images/z19_yw_2025tab2.png	0.0 ms	2.4 KiB
www.cas.cn/images/z19_search_m.png	0.0 ms	2.4 KiB
www.cas.cn/images/z19_index_yw1.png	0.0 ms	2.2 KiB
www.cas.cn/images/z19_pc_m.png	0.0 ms	2.2 KiB
www.cas.cn/images/z19_index_xk1.png	0.0 ms	2.0 KiB
www.cas.cn/images/z19_h5.js	0.0 ms	2.0 KiB
www.cas.cn/images/z19_video_play.png	0.0 ms	1.9 KiB
www.cas.cn/images/z19_jl_bg.jpg	0.0 ms	1.7 KiB
www.cas.cn/images/z19_en_m.png	0.0 ms	1.7 KiB
www.cas.cn/images/z19_index_tz2.png	0.0 ms	1.7 KiB
www.cas.cn/images/foot_jgawb.png	0.0 ms	1.6 KiB
www.cas.cn/images/z19_index_tj.png	0.0 ms	1.6 KiB
www.cas.cn/images/z19_nav_up.png	0.0 ms	1.4 KiB
www.cas.cn/images/z19_index_xk2.png	0.0 ms	1.4 KiB
www.cas.cn/lib/js/plugin/topSide.min.js	0.0 ms	1.4 KiB
www.cas.cn/images/z19_focus_left.png	0.0 ms	1.3 KiB
www.cas.cn/images/z19_focus_right.png	0.0 ms	1.3 KiB
www.cas.cn/images/z19_resize.js	0.0 ms	1.3 KiB
www.cas.cn/images/z19_xk_tab_pad.png	0.0 ms	1.3 KiB
www.cas.cn/images/z19_index_tz1.png	0.0 ms	1.2 KiB
www.cas.cn/images/z19_bg_blue2.png	0.0 ms	1.2 KiB
www.cas.cn/images/z19_index_ky1.png	0.0 ms	1.2 KiB
www.cas.cn/images/z19_scroll_top.png	0.0 ms	1.1 KiB
www.cas.cn/images/z19_index_ft1.png	0.0 ms	1.0 KiB
www.cas.cn/images/z19_index_video1.png	0.0 ms	1.0 KiB
www.cas.cn/images/z19_index_video2.png	0.0 ms	1020 B
www.cas.cn/images/z19_jl_img.png	0.0 ms	919 B
www.cas.cn/images/z19_index_zt1.png	0.0 ms	877 B
www.cas.cn/images/z19_index_ky2.png	0.0 ms	750 B
www.cas.cn/images/z19_index_ft2.png	0.0 ms	750 B
www.cas.cn/images/z19_index_gz2.png	0.0 ms	727 B
www.cas.cn/images/z19_index_gz1.png	0.0 ms	689 B
www.cas.cn/images/z19_search.png	0.0 ms	647 B
www.cas.cn/images/z19_news_list.png	0.0 ms	597 B
www.cas.cn/images/z19_bg_blue.png	0.0 ms	539 B
www.cas.cn/images/z19_xk_tab.png	0.0 ms	485 B
www.cas.cn/images/z19_xk_list.png	0.0 ms	318 B

Layout shifts occur when elements move absent any user interaction. Investigate the causes of layout shifts, such as elements being added, removed, or their fonts changing as the page loads.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:node label:Element subItemsHeading:map[key:extra] valueType:node] map[granularity:0.001 key:score label:Layout shift score subItemsHeading:map[key:cause valueType:text] valueType:numeric]]

items: [map[node:map[type:text value:Total] score:0.626579] map[node:map[boundingRect:map[bottom:2292 height:1321 left:48 right:1302 top:971 width:1254] lhId:page-33-DIV nodeLabel:要闻播报院内要闻更多院内要闻 + 中央第十三巡视组巡视中国科学院党组工作动员会召开 2026年04月14日中央第十三巡视组巡视中国科学院党组工作动员会召… path:1,HTML,1,BODY,14,DIV,6,DIV selector:body > div.container > div.row snippet:<div class="row clearfix"> type:node] score:0.362307 subItems:map[items:[map[cause:Unsized image element extra:map[boundingRect:map[bottom:1009 height:30 left:68 right:98 top:979 width:30] lhId:page-50-IMG nodeLabel:ul.tab_title > li.tab_title_yw1 > a > img path:1,HTML,1,BODY,14,DIV,6,DIV,1,DIV,1,DIV,0,UL,0,LI,0,A,0,IMG selector:ul.tab_title > li.tab_title_yw1 > a > img snippet:<img src="//www.cas.cn/images/z19_index_yw1.png"> type:node]]] type:subitems]] map[node:map[boundingRect:map[bottom:2292 height:1321 left:48 right:1302 top:971 width:1254] lhId:page-33-DIV nodeLabel:要闻播报院内要闻更多院内要闻 + 中央第十三巡视组巡视中国科学院党组工作动员会召开 2026年04月14日中央第十三巡视组巡视中国科学院党组工作动员会召… path:1,HTML,1,BODY,14,DIV,6,DIV selector:body > div.container > div.row snippet:<div class="row clearfix"> type:node] score:0.160445 subItems:map[items:[map[cause:Unsized image element extra:map[boundingRect:map[bottom:1009 height:30 left:68 right:98 top:979 width:30] lhId:page-50-IMG nodeLabel:ul.tab_title > li.tab_title_yw1 > a > img path:1,HTML,1,BODY,14,DIV,6,DIV,1,DIV,1,DIV,0,UL,0,LI,0,A,0,IMG selector:ul.tab_title > li.tab_title_yw1 > a > img snippet:<img src="//www.cas.cn/images/z19_index_yw1.png"> type:node]]] type:subitems]] map[node:map[boundingRect:map[bottom:2432 height:2122 left:48 right:1302 top:310 width:1254] lhId:page-29-DIV nodeLabel:习近平同莫桑比克总统查波举行会谈中科院之声专题：改革创新发展这五年中国科学院深入开展树立和践行正确政绩观学习教育科学家发现野生稻多年生生活习性关键… path:1,HTML,1,BODY,14,DIV selector:body > div.container snippet:<div class="container boxcenter main index_add2025"> type:node] score:0.097845 subItems:map[items:[map[cause:Unsized image element extra:map[boundingRect:map[bottom:134 height:60 left:48 right:308 top:74 width:260] lhId:page-25-IMG nodeLabel:div.top2 > div.container > a.xsdlogotop > img.logo path:1,HTML,1,BODY,5,DIV,0,DIV,0,A,0,IMG selector:div.top2 > div.container > a.xsdlogotop > img.logo snippet:<img src="//www.cas.cn/images/z19_logo.png" class="logo fl_all"> type:node]]] type:subitems]] map[node:map[boundingRect:map[bottom:1181 height:146 left:48 right:264 top:1035 width:216] lhId:page-7-IMG nodeLabel:div.tab_con > div.yw_img > a > img.hvr-grow path:1,HTML,1,BODY,14,DIV,6,DIV,1,DIV,1,DIV,1,DIV,4,DIV,1,DIV,0,A,0,IMG selector:div.tab_con > div.yw_img > a > img.hvr-grow snippet:<img src="./yw/202604/W020260414668107692283_ORIGIN.jpg" class="hvr-grow"> type:node] score:0.005899 subItems:map[items:[map[cause:Unsized image element extra:map[boundingRect:map[bottom:1466 height:28 left:62 right:90 top:1438 width:28] lhId:page-49-IMG nodeLabel:ul.tab_title > li.now > a > img path:1,HTML,1,BODY,14,DIV,6,DIV,1,DIV,4,DIV,0,UL,0,LI,0,A,0,IMG selector:ul.tab_title > li.now > a > img snippet:<img src="//www.cas.cn/images/z19_index_ky1.png"> type:node]]] type:subitems]] map[node:map[boundingRect:map[bottom:1462 height:20 left:174 right:178 top:1442 width:4] lhId:page-32-SPAN nodeLabel:| path:1,HTML,1,BODY,14,DIV,6,DIV,1,DIV,4,DIV,0,UL,0,LI,0,A,2,SPAN selector:ul.tab_title > li.now > a > span snippet:<span> type:node] score:8.3e-05 subItems:map[items:[map[cause:Unsized image element extra:map[boundingRect:map[bottom:1466 height:28 left:62 right:90 top:1438 width:28] lhId:page-49-IMG nodeLabel:ul.tab_title > li.now > a > img path:1,HTML,1,BODY,14,DIV,6,DIV,1,DIV,4,DIV,0,UL,0,LI,0,A,0,IMG selector:ul.tab_title > li.now > a > img snippet:<img src="//www.cas.cn/images/z19_index_ky1.png"> type:node]]] type:subitems]]]

items: [map[node:map[type:text value:Total] score:0.214815] map[node:map[boundingRect:map[bottom:2432 height:2122 left:48 right:1302 top:310 width:1254] lhId:page-29-DIV nodeLabel:习近平同莫桑比克总统查波举行会谈中科院之声专题：改革创新发展这五年中国科学院深入开展树立和践行正确政绩观学习教育科学家发现野生稻多年生生活习性关键… path:1,HTML,1,BODY,14,DIV selector:body > div.container snippet:<div class="container boxcenter main index_add2025"> type:node] score:0.214815]]

items: [map[node:map[type:text value:Total] score:0.115954] map[node:map[boundingRect:map[bottom:921 height:511 left:-2460 right:-1206 top:410 width:1254] lhId:page-44-LI nodeLabel:科学家发现野生稻多年生生活习性关键基因 path:1,HTML,1,BODY,14,DIV,2,DIV,0,DIV,0,UL,2,LI selector:div.m_index_focus > div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide snippet:<li class="swiper-slide" style="width: 1254px; height: 511px;"> type:node] score:0.115954 subItems:map[items:[map[cause:Unsized image element extra:map[boundingRect:map[bottom:1009 height:30 left:68 right:98 top:979 width:30] lhId:page-50-IMG nodeLabel:ul.tab_title > li.tab_title_yw1 > a > img path:1,HTML,1,BODY,14,DIV,6,DIV,1,DIV,1,DIV,0,UL,0,LI,0,A,0,IMG selector:ul.tab_title > li.tab_title_yw1 > a > img snippet:<img src="//www.cas.cn/images/z19_index_yw1.png"> type:node]]] type:subitems]]]

items: [map[node:map[type:text value:Total] score:4e-06] map[node:map[boundingRect:map[bottom:900 height:14 left:1178 right:1192 top:886 width:14] lhId:page-48-SPAN nodeLabel:div.container > div.m_index_focus > div.pagination > span.swiper-pagination-switch path:1,HTML,1,BODY,14,DIV,2,DIV,1,DIV,2,SPAN selector:div.container > div.m_index_focus > div.pagination > span.swiper-pagination-switch snippet:<span class="swiper-pagination-switch"> type:node] score:4e-06 subItems:map[items:[map[cause:Unsized image element extra:map[boundingRect:map[bottom:885 height:475 left:3810 right:5064 top:410 width:1254] lhId:page-1-IMG nodeLabel:ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc path:1,HTML,1,BODY,14,DIV,2,DIV,0,DIV,0,UL,7,LI,0,A,0,IMG selector:ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc snippet:<img src="./gd/202603/W020260304562615519478_ORIGIN.jpg" class="focus_img_pc"> type:node]]] type:subitems]]]

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Resource Size	Est Savings
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`	www.cas.cn/gd/202603/W020260320367237873144_ORIGIN.jpg	622.4 KiB	525.5 KiB
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`	www.cas.cn/gd/202603/W020260304562615519478_ORIGIN.jpg	456.6 KiB	359.7 KiB
body > div.top2 > div.container `body > div.top2 > div.container`	www.cas.cn/images/topbgimg_20251217.png	441.6 KiB	354.9 KiB
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`	www.cas.cn/gd/202603/W020260305339535003381_ORIGIN.jpg	366.5 KiB	269.5 KiB
div.tab_con > div.ky_img > a > img.hvr-grow `div.tab_con > div.ky_img > a > img.hvr-grow`	www.cas.cn/sygz/202604/W020260416563069960778.png	267.5 KiB	263.9 KiB
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`	www.cas.cn/gd/202603/W020260304562615738276_ORIGIN.jpg	266.6 KiB	210.9 KiB
div.tab_con > div.video_left > a > img `div.tab_con > div.video_left > a > img`	www.cas.cn/spx/202604/W020260420379180266731_ORIGIN.jpg	216.8 KiB	209.2 KiB
div.tab_con > div.yw_img > a > img.hvr-grow `div.tab_con > div.yw_img > a > img.hvr-grow`	www.cas.cn/yw/202604/W020260414668107692283_ORIGIN.jpg	192.7 KiB	173.4 KiB
© 1996 - 2026 中国科学院版权所有　京ICP备05002857号-1　京公网安备110402500047号　网站标识码bm48000002 地… `body > div.foot`	www.cas.cn/images/z19_foot.png	208.5 KiB	165.7 KiB
div.tab_con > div.ky_img > a > img.hvr-grow `div.tab_con > div.ky_img > a > img.hvr-grow`	www.cas.cn/syky/202604/W020260421315832007785_ORIGIN.jpg	141.6 KiB	138.0 KiB
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`	www.cas.cn/gd/202601/W020260128305083603703_ORIGIN.jpg	229.8 KiB	132.9 KiB
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`	www.cas.cn/gd/202603/W020260303457407403045_ORIGIN.jpg	212.2 KiB	115.2 KiB
div.divBox > div.zt > a > img.hvr-grow `div.divBox > div.zt > a > img.hvr-grow`	www.cas.cn/zt1/202604/W020260401410085460301.jpg	94.6 KiB	90.7 KiB
div.divBox > div.zt > a.mar0 > img.hvr-grow `div.divBox > div.zt > a.mar0 > img.hvr-grow`	www.cas.cn/zt1/202603/W020260320378579484579.jpg	88.1 KiB	84.1 KiB
div.divBox > div.zt > a > img.hvr-grow `div.divBox > div.zt > a > img.hvr-grow`	www.cas.cn/zt1/202604/W020260401410081532588.jpg	82.2 KiB	78.3 KiB
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_m`	www.cas.cn/gd/202601/W020260121572218060263_ORIGIN.jpg	121.0 KiB	65.4 KiB
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`	www.cas.cn/images/z19_tj_img1.jpg	52.9 KiB	51.7 KiB
ul.videoBox > li.hvr-grow-img > a > img.hvr-grow `ul.videoBox > li.hvr-grow-img > a > img.hvr-grow`	www.cas.cn/images/zjzkypc_202303.jpg	47.1 KiB	43.5 KiB
中科院之声 `div.container > div.topTitle > a > div.img_video`	www.cas.cn/images/zkyzspc_202303.jpg	36.7 KiB	31.5 KiB
ul.videoBox > li.hvr-grow-img > a > img.hvr-grow `ul.videoBox > li.hvr-grow-img > a > img.hvr-grow`	www.cas.cn/images/zjxbpc_202303.jpg	34.3 KiB	30.7 KiB
div.clearfix > div.videopad > a > img `div.clearfix > div.videopad > a > img`	www.cas.cn/syzc/202312/W020231229530488598921_ORIGIN.jpg	56.1 KiB	26.4 KiB
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`	www.cas.cn/gd/202601/W020260121576547305038_ORIGIN.jpg	123.1 KiB	26.1 KiB
div.top2 > div.container > div.xsdadd-2025 > img.xsdimg01 `div.top2 > div.container > div.xsdadd-2025 > img.xsdimg01`	www.cas.cn/images/dsb02_20251217.png	35.8 KiB	20.5 KiB
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`	www.cas.cn/images/yjzxgl_202203826.jpg	21.2 KiB	19.9 KiB
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`	www.cas.cn/images/z19_tj_img3.jpg	15.0 KiB	13.7 KiB
div.top2 > div.container > a.xsdlogotop > img.logo `div.top2 > div.container > a.xsdlogotop > img.logo`	www.cas.cn/images/z19_logo.png	16.0 KiB	13.5 KiB
div.top2 > div.container > a.xsdlogotop > img.logobtmxsd `div.top2 > div.container > a.xsdlogotop > img.logobtmxsd`	www.cas.cn/images/dsb01_20251217.png	18.0 KiB	12.5 KiB
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`	www.cas.cn/images/z19_index_yw2.png	4.4 KiB	4.3 KiB

Each subpart has specific improvement strategies. Ideally, most of the LCP time should be spent on loading the resources, not within delays.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:label label:Subpart valueType:text] map[key:duration label:Duration valueType:ms]]

items: [map[duration:2198.0220009765626 label:Time to first byte subpart:timeToFirstByte] map[duration:271.4619990234375 label:Resource load delay subpart:resourceLoadDelay] map[duration:9444.342 label:Resource load duration subpart:resourceLoadDuration] map[duration:16.958 label:Element render delay subpart:elementRenderDelay]]

lhId: page-28-IMG

nodeLabel: ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc

path: 1,HTML,1,BODY,14,DIV,2,DIV,0,DIV,0,UL,1,LI,0,A,0,IMG

selector: ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc

snippet: <img src="./gd/202603/W020260304562615519478_ORIGIN.jpg" class="focus_img_pc">

Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading

Why this matters

Performance issues directly impact user engagement and conversion rates.

lhId: page-28-IMG

nodeLabel: ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc

path: 1,HTML,1,BODY,14,DIV,2,DIV,0,DIV,0,UL,1,LI,0,A,0,IMG

selector: ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc

snippet: <img src="./gd/202603/W020260304562615519478_ORIGIN.jpg" class="focus_img_pc">

HTTP/2 and HTTP/3 offer many benefits over HTTP/1.1, such as multiplexing. Learn more about using modern HTTP.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Protocol
www.cas.cn/	http/1.1
www.cas.cn/lib/js/plugin/swiper/swiper.min.css	http/1.1
www.cas.cn/lib/css/hover.css	http/1.1
www.cas.cn/images/z19_public.css?v=20251218	http/1.1
www.cas.cn/images/z19_index.css?v=20251225	http/1.1
www.cas.cn/images/z19_stylePad.css	http/1.1
www.cas.cn/images/z19_logo.png	http/1.1
www.cas.cn/images/dsb01_20251217.png	http/1.1
www.cas.cn/images/dsb02_20251217.png	http/1.1
www.cas.cn/images/z19_pc_m.png	http/1.1
www.cas.cn/images/z19_en_m.png	http/1.1
www.cas.cn/images/wza_2024.png	http/1.1
www.cas.cn/images/z19_search_m.png	http/1.1
www.cas.cn/images/z19_close.png	http/1.1
www.cas.cn/zz/yld/201803/W020191125383560116474.jpg	http/1.1
www.cas.cn/zz/yld/202404/W020240407367171999355_ORIGIN.jpg	http/1.1
www.cas.cn/zz/yld/201704/W020190929738332637068.jpg	http/1.1
www.cas.cn/zz/yld/201909/W020201118270525579945.jpg	http/1.1
www.cas.cn/zz/yld/201605/W020190929739561066807.jpg	http/1.1
www.cas.cn/zz/yld/202308/W020240329553856002424_ORIGIN.jpg	http/1.1
www.cas.cn/zz/yld/202409/W020240912524118761361_ORIGIN.jpg	http/1.1
www.cas.cn/zz/yld/202311/W020231122659760924736.jpg	http/1.1
www.cas.cn/zz/yld/202504/W020250406365313605807_ORIGIN.jpg	http/1.1
www.cas.cn/zz/yld/202504/W020250406366075798999_ORIGIN.jpg	http/1.1
www.cas.cn/zz/yld/202504/W020250416559005659783_ORIGIN.jpg	http/1.1
www.cas.cn/kxyj/202512/W020251218541107090958_ORIGIN.jpg	http/1.1
www.cas.cn/kxyj/202512/W020251218633030399800.jpg	http/1.1
www.cas.cn/images/z19_kxyj_img2.jpg	http/1.1
www.cas.cn/images/20260309_navkjqk.png	http/1.1
www.cas.cn/images/20220826kejitop.jpg	http/1.1
www.cas.cn/cg/112072/images/P020190929620050824644.jpg	http/1.1
www.cas.cn/images/z19_school1.jpg	http/1.1
www.cas.cn/images/z19_school2.jpg	http/1.1
www.cas.cn/images/z19_school3.jpg	http/1.1
www.cas.cn/images/z19_school_bar1.jpg	http/1.1
www.cas.cn/images/z19_school_bar2.jpg	http/1.1
www.cas.cn/images/z19_school_bar3.jpg	http/1.1
www.cas.cn/kx/202404/W020240510574946875857_ORIGIN.jpg	http/1.1
www.cas.cn/kx/202404/W020240510575174145626_ORIGIN.jpg	http/1.1
www.cas.cn/images/z2025_dqgz1.jpg	http/1.1
www.cas.cn/images/z19_dqgz2.jpg	http/1.1
www.cas.cn/gd/202603/W020260304562615519478_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202603/W020260304562615738276_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202603/W020260320367237873144_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202603/W020260320373519199299_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202603/W020260303457407403045_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202603/W020260303457407615596_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202603/W020260305339535003381_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202603/W020260305339535231140_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202601/W020260128305083603703_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202601/W020260128305083857947_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202601/W020260121576547305038_ORIGIN.jpg	http/1.1
www.cas.cn/gd/202601/W020260121572218060263_ORIGIN.jpg	http/1.1
www.cas.cn/syzc/202312/W020231229530488598921_ORIGIN.jpg	http/1.1
www.cas.cn/images/z19_index_yw1.png	http/1.1
www.cas.cn/images/z19_index_yw2.png	http/1.1
www.cas.cn/gj/202604/W020260421522038092312.png	http/1.1
www.cas.cn/yw/202604/W020260414668107692283_ORIGIN.jpg	http/1.1
www.cas.cn/images/z19_index_ky1.png	http/1.1
www.cas.cn/images/z19_index_ky2.png	http/1.1
www.cas.cn/syky/202604/W020260421315832007785_ORIGIN.jpg	http/1.1
www.cas.cn/cm/202604/W020260421385309959198.png	http/1.1
www.cas.cn/images/z19_index_gz1.png	http/1.1
www.cas.cn/images/z19_index_gz2.png	http/1.1
www.cas.cn/sygz/202604/W020260416563069960778.png	http/1.1
www.cas.cn/yx/202603/W020260324417741201243.png	http/1.1
www.cas.cn/images/z19_index_zt1.png	http/1.1
www.cas.cn/zt1/202604/W020260401410085460301.jpg	http/1.1
www.cas.cn/zt1/202604/W020260401410081532588.jpg	http/1.1
www.cas.cn/zt1/202603/W020260320378579484579.jpg	http/1.1
www.cas.cn/images/z19_jl_img.png	http/1.1
www.cas.cn/images/zjzkypc_202303.jpg	http/1.1
www.cas.cn/images/zjzkymob_202303.jpg	http/1.1
www.cas.cn/images/zjxbpc_202303.jpg	http/1.1
www.cas.cn/images/zjxbmob_202303.jpg	http/1.1
www.cas.cn/images/zkyzsmob_202303.jpg	http/1.1
www.cas.cn/images/z19_index_tz1.png	http/1.1
www.cas.cn/images/z19_index_tz2.png	http/1.1
www.cas.cn/images/z19_index_video1.png	http/1.1
www.cas.cn/images/z19_index_video2.png	http/1.1
www.cas.cn/spx/202604/W020260420379180266731_ORIGIN.jpg	http/1.1
www.cas.cn/images/z19_video_play.png	http/1.1
www.cas.cn/spx/202604/W020260418314827276324_ORIGIN.jpg	http/1.1
www.cas.cn/spx/202604/W020260417530461254188_ORIGIN.jpg	http/1.1
www.cas.cn/newmedia/dsp/202604/W020260421276040437486.jpg	http/1.1
www.cas.cn/newmedia/dsp/202604/W020260420329652831168.png	http/1.1
www.cas.cn/newmedia/dsp/202604/W020260421546988627746.png	http/1.1
www.cas.cn/images/z19_index_xk2.png	http/1.1
www.cas.cn/images/z19_index_xk1.png	http/1.1
www.cas.cn/images/z19_index_ft1.png	http/1.1
www.cas.cn/images/z19_index_ft2.png	http/1.1
www.cas.cn/images/20230731zcjd.jpg	http/1.1
www.cas.cn/images/swiper.min.js	http/1.1
www.cas.cn/images/z19_jl_icon2.png	http/1.1
www.cas.cn/images/z19_jl_icon4.png	http/1.1
www.cas.cn/images/z19_jl_icon5.png	http/1.1
www.cas.cn/images/z22_jl_xfqd.png	http/1.1
www.cas.cn/images/z19_index_tj.png	http/1.1
www.cas.cn/images/z19_tj_img3.jpg	http/1.1
www.cas.cn/images/z19_tj_img1.jpg	http/1.1
www.cas.cn/images/yjzxgl_202203826.jpg	http/1.1
www.cas.cn/images/z19_scroll_wb.png	http/1.1
www.cas.cn/images/z19_scroll_wx.png	http/1.1
www.cas.cn/images/z19_ewm3.jpg	http/1.1
www.cas.cn/images/z19_scroll_top.png	http/1.1
www.cas.cn/images/z19_return_m.png	http/1.1
www.cas.cn/images/foot_jgawb.png	http/1.1
www.cas.cn/images/jiucuo.png	http/1.1
www.cas.cn/images/blue.png	http/1.1
www.cas.cn/images/z19_gopc.png	http/1.1
www.cas.cn/lib/js/jquery.min.js	http/1.1
www.cas.cn/images/z19_h5.js	http/1.1
www.cas.cn/lib/js/plugin/swiper/idangerous.swiper.min.js	http/1.1
www.cas.cn/lib/js/plugin/jquery.cookie.js	http/1.1
www.cas.cn/images/z19_main.js?v=1.0	http/1.1
www.cas.cn/images/z19_resize.js	http/1.1
www.cas.cn/lib/js/plugin/wza/esdtoolsinit.js	http/1.1
www.cas.cn/lib/js/plugin/topSide.min.js	http/1.1
www.cas.cn/images/z19_search.png	http/1.1
www.cas.cn/images/topbgimg_20251217.png	http/1.1
www.cas.cn/images/z19_nav_up.png	http/1.1
www.cas.cn/images/z19_focus_right.png	http/1.1
www.cas.cn/images/z19_focus_left.png	http/1.1
www.cas.cn/images/z19_yw_2025tab2.png	http/1.1
www.cas.cn/images/z19_news_list.png	http/1.1
www.cas.cn/images/z19_xk_list.png	http/1.1
www.cas.cn/images/z19_bg_blue.png	http/1.1
www.cas.cn/images/z19_xk_tab_pad.png	http/1.1
www.cas.cn/images/z19_bg_blue2.png	http/1.1
www.cas.cn/images/z19_jl_bg.jpg	http/1.1
www.cas.cn/images/z19_foot_m.jpg	http/1.1
www.cas.cn/images/zkyzspc_202303.jpg	http/1.1
www.cas.cn/images/z19_xk_tab.png	http/1.1
www.cas.cn/images/z19_foot.png	http/1.1
www.cas.cn/lib/images/favicon.ico	http/1.1

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Why this matters

Performance issues directly impact user engagement and conversion rates.

title: Preconnected origins

value: no origins were preconnected

description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.

title: Preconnect candidates

value: No additional origins are good candidates for preconnecting

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size	Duration
www.cas.cn/images/z19_public.css?v=20251218	24.6 KiB	205 ms
www.cas.cn/lib/css/hover.css	116.2 KiB	325 ms
www.cas.cn/images/z19_stylePad.css	12.1 KiB	165 ms
www.cas.cn/images/z19_index.css?v=20251225	13.2 KiB	165 ms
www.cas.cn/lib/js/plugin/swiper/swiper.min.css	19.5 KiB	85 ms

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 399 ms

URL	Time Spent
cas.cn/	209 ms
www.cas.cn/	190 ms
www.cas.cn/	0.0 ms

These are the largest layout shifts observed on the page. Each table item represents a single layout shift, and shows the element that shifted the most. Below each item are possible root causes that led to the layout shift. Some of these layout shifts may not be included in the CLS metric value due to windowing. Learn how to improve CLS

Why this matters

Performance issues directly impact user engagement and conversion rates.

Element	Layout shift score
要闻播报院内要闻更多院内要闻 + 中央第十三巡视组巡视中国科学院党组工作动员会召开 2026年04月14日中央第十三巡视组巡视中国科学院党组工作动员会召… `body > div.container > div.row`	0.362
习近平同莫桑比克总统查波举行会谈中科院之声专题：改革创新发展这五年中国科学院深入开展树立和践行正确政绩观学习教育科学家发现野生稻多年生生活习性关键… `body > div.container`	0.215
要闻播报院内要闻更多院内要闻 + 中央第十三巡视组巡视中国科学院党组工作动员会召开 2026年04月14日中央第十三巡视组巡视中国科学院党组工作动员会召… `body > div.container > div.row`	0.160
科学家发现野生稻多年生生活习性关键基因 `div.m_index_focus > div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide`	0.116
习近平同莫桑比克总统查波举行会谈中科院之声专题：改革创新发展这五年中国科学院深入开展树立和践行正确政绩观学习教育科学家发现野生稻多年生生活习性关键… `body > div.container`	0.098
div.tab_con > div.yw_img > a > img.hvr-grow `div.tab_con > div.yw_img > a > img.hvr-grow`	0.006
\| `ul.tab_title > li.now > a > span`	0.000
div.container > div.m_index_focus > div.pagination > span.swiper-pagination-switch `div.container > div.m_index_focus > div.pagination > span.swiper-pagination-switch`	0.000

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

Diagnostics

Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 20 ms 21.8 KiB

URL	Transfer Size	Est Savings
www.cas.cn/lib/css/hover.css	116.2 KiB	18.8 KiB
www.cas.cn/images/z19_public.css?v=20251218	24.6 KiB	3.0 KiB

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 110 ms 152.3 KiB

URL	Transfer Size	Est Savings
www.cas.cn/lib/css/hover.css	116.0 KiB	115.7 KiB
www.cas.cn/images/z19_public.css?v=20251218	24.4 KiB	19.0 KiB
www.cas.cn/lib/js/plugin/swiper/swiper.min.css	19.3 KiB	17.6 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Why this matters

Multi-megabyte JavaScript bundles delay every interactive feature on the page.

Learn more ▾

Source: Google web.dev / Lighthouse

Estimated savings: 80 ms 110.7 KiB

URL	Transfer Size	Est Savings
www.cas.cn/images/swiper.min.js	94.2 KiB	58.6 KiB
www.cas.cn/lib/js/jquery.min.js	94.9 KiB	52.1 KiB

Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 0.0 ms 2.5 KiB

URL	Transfer Size	Est Savings
www.cas.cn/images/z19_main.js?v=1.0	12.8 KiB	2.5 KiB

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size
www.cas.cn/gd/202603/W020260320367237873144_ORIGIN.jpg	622.6 KiB
www.cas.cn/gd/202603/W020260304562615519478_ORIGIN.jpg	456.8 KiB
www.cas.cn/yx/202603/W020260324417741201243.png	454.2 KiB
www.cas.cn/images/topbgimg_20251217.png	441.8 KiB
www.cas.cn/gd/202603/W020260320373519199299_ORIGIN.jpg	387.9 KiB
www.cas.cn/gd/202603/W020260305339535003381_ORIGIN.jpg	366.7 KiB
www.cas.cn/gj/202604/W020260421522038092312.png	350.4 KiB
www.cas.cn/cm/202604/W020260421385309959198.png	280.4 KiB
www.cas.cn/newmedia/dsp/202604/W020260420329652831168.png	269.6 KiB
www.cas.cn/sygz/202604/W020260416563069960778.png	267.7 KiB

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`	www.cas.cn/gd/202601/W020260121576547305038_ORIGIN.jpg
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`	www.cas.cn/gd/202603/W020260304562615519478_ORIGIN.jpg
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`	www.cas.cn/gd/202603/W020260320367237873144_ORIGIN.jpg
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`	www.cas.cn/gd/202603/W020260303457407403045_ORIGIN.jpg
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`	www.cas.cn/gd/202603/W020260305339535003381_ORIGIN.jpg
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`	www.cas.cn/gd/202601/W020260128305083603703_ORIGIN.jpg
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`	www.cas.cn/gd/202601/W020260121576547305038_ORIGIN.jpg
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`	www.cas.cn/gd/202603/W020260304562615519478_ORIGIN.jpg
div.tab_con > div.ky_img > a > img.hvr-grow `div.tab_con > div.ky_img > a > img.hvr-grow`	www.cas.cn/syky/202604/W020260421315832007785_ORIGIN.jpg
div.tab_con > div.ky_img > a > img.hvr-grow `div.tab_con > div.ky_img > a > img.hvr-grow`	www.cas.cn/sygz/202604/W020260416563069960778.png
div.top2 > div.container > div.xsdadd-2025 > img.xsdimg01 `div.top2 > div.container > div.xsdadd-2025 > img.xsdimg01`	www.cas.cn/images/dsb02_20251217.png
div.divBox > div.zt > a > img.hvr-grow `div.divBox > div.zt > a > img.hvr-grow`	www.cas.cn/zt1/202604/W020260401410085460301.jpg
div.divBox > div.zt > a > img.hvr-grow `div.divBox > div.zt > a > img.hvr-grow`	www.cas.cn/zt1/202604/W020260401410081532588.jpg
div.divBox > div.zt > a.mar0 > img.hvr-grow `div.divBox > div.zt > a.mar0 > img.hvr-grow`	www.cas.cn/zt1/202603/W020260320378579484579.jpg
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`	www.cas.cn/images/z19_tj_img3.jpg
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`	www.cas.cn/images/z19_tj_img1.jpg
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`	www.cas.cn/images/yjzxgl_202203826.jpg
div.top2 > div.container > a.xsdlogotop > img.logobtmxsd `div.top2 > div.container > a.xsdlogotop > img.logobtmxsd`	www.cas.cn/images/dsb01_20251217.png
div.top2 > div.container > a.xsdlogotop > img.logo `div.top2 > div.container > a.xsdlogotop > img.logo`	www.cas.cn/images/z19_logo.png
ul.tab_title > li.tab_title_yw1 > a > img `ul.tab_title > li.tab_title_yw1 > a > img`	www.cas.cn/images/z19_index_yw1.png
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`	www.cas.cn/images/z19_index_yw2.png
li > span#_ideConac > a > img#imgConac `li > span#_ideConac > a > img#imgConac`	www.cas.cn/images/blue.png
div.Rightfixed > div.RF_box > a > img `div.Rightfixed > div.RF_box > a > img`	www.cas.cn/images/z19_scroll_wb.png
div.container > div.Rightfixed > div.RF_box > img `div.container > div.Rightfixed > div.RF_box > img`	www.cas.cn/images/z19_scroll_wx.png
li > span#_span_jiucuo > a > img `li > span#_span_jiucuo > a > img`	www.cas.cn/images/jiucuo.png
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`	www.cas.cn/images/z19_index_ky1.png
ul.tab_title > li > a > img `ul.tab_title > li > a > img`	www.cas.cn/images/z19_index_ky2.png
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`	www.cas.cn/images/z19_index_gz1.png
ul.tab_title > li > a > img `ul.tab_title > li > a > img`	www.cas.cn/images/z19_index_gz2.png
div.divBox > div.div_title > p > img `div.divBox > div.div_title > p > img`	www.cas.cn/images/z19_index_zt1.png
div.divBox > div.jl > div.jl_left > img `div.divBox > div.jl > div.jl_left > img`	www.cas.cn/images/z19_jl_img.png
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`	www.cas.cn/images/z19_index_tz1.png
ul.tab_title > li > a > img `ul.tab_title > li > a > img`	www.cas.cn/images/z19_index_tz2.png
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`	www.cas.cn/images/z19_index_video1.png
ul.tab_title > li > a > img `ul.tab_title > li > a > img`	www.cas.cn/images/z19_index_video2.png
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`	www.cas.cn/images/z19_index_xk2.png
ul.tab_title > li > a > img `ul.tab_title > li > a > img`	www.cas.cn/images/z19_index_xk1.png
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`	www.cas.cn/images/z19_index_ft1.png
ul.tab_title > li > a > img `ul.tab_title > li > a > img`	www.cas.cn/images/z19_index_ft2.png
div.tj > div.div_title > p > img `div.tj > div.div_title > p > img`	www.cas.cn/images/z19_index_tj.png
div.boxcenter > div.foot_txt > p > img `div.boxcenter > div.foot_txt > p > img`	www.cas.cn/images/foot_jgawb.png

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Optimize DOM size

●Font display

●Forced reflow

●Optimize viewport for mobile

●Max Potential First Input Delay 20 ms

●JavaScript execution time 0.0 s

●Minimizes main-thread work 0.8 s

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 270 ms

●Server Backend Latencies 10 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Initial server response time was short Root document took 280 ms

○INP breakdown

○User Timing marks and measures

○Avoid long main-thread tasks

○Avoid non-composited animations

Accessibility

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
English / 联系我们 / 网站地图 /邮箱 /无障碍 /关怀版 `div.top1 > div.container > div.top_r > div.top_link`
English `div.container > div.top_r > div.top_link > a`
2026年04月14日 `div.tab_con > div.yw_img > div.date > span`
2026年02月11日 `div.tab_con > ul.tzgg > li > p`
2026年04月20日 `div.tab_con > ul.tzgg > li > p`

These are opportunities to improve the legibility of your content.

Internationalization and localization

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
html `html`

These are opportunities to improve the interpretation of your content by users in different locales.

Names and labels

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.top2 > div.container > a.xsdlogotop > img.logo `div.top2 > div.container > a.xsdlogotop > img.logo`
div.top2 > div.container > a.xsdlogotop > img.logobtmxsd `div.top2 > div.container > a.xsdlogotop > img.logobtmxsd`
div.top2 > div.container > div.xsdadd-2025 > img.xsdimg01 `div.top2 > div.container > div.xsdadd-2025 > img.xsdimg01`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.tab_title > li.tab_title_yw1 > a > img `ul.tab_title > li.tab_title_yw1 > a > img`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
div.tab_con > div.yw_img > a > img.hvr-grow `div.tab_con > div.yw_img > a > img.hvr-grow`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.tab_con > div.ky_img > a > img.hvr-grow `div.tab_con > div.ky_img > a > img.hvr-grow`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.tab_con > div.ky_img > a > img.hvr-grow `div.tab_con > div.ky_img > a > img.hvr-grow`
div.divBox > div.div_title > p > img `div.divBox > div.div_title > p > img`
div.divBox > div.zt > a > img.hvr-grow `div.divBox > div.zt > a > img.hvr-grow`
div.divBox > div.zt > a > img.hvr-grow `div.divBox > div.zt > a > img.hvr-grow`
div.divBox > div.zt > a.mar0 > img.hvr-grow `div.divBox > div.zt > a.mar0 > img.hvr-grow`
div.divBox > div.jl > div.jl_left > img `div.divBox > div.jl > div.jl_left > img`
ul.videoBox > li.hvr-grow-img > a > img `ul.videoBox > li.hvr-grow-img > a > img`
ul.videoBox > li.hvr-grow-img > a > img.hvr-grow `ul.videoBox > li.hvr-grow-img > a > img.hvr-grow`
ul.videoBox > li.hvr-grow-img > a > img.hvr-grow `ul.videoBox > li.hvr-grow-img > a > img.hvr-grow`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.tab_con > div.video_left > a > img `div.tab_con > div.video_left > a > img`
div.tab_con > div.video_left > a > img.video_play2 `div.tab_con > div.video_left > a > img.video_play2`
div.video_right > div.video_img > a > img `div.video_right > div.video_img > a > img`
div.video_right > div.video_img > a > img.video_play2 `div.video_right > div.video_img > a > img.video_play2`
div.video_right > div.video_img > a > img `div.video_right > div.video_img > a > img`
div.video_right > div.video_img > a > img.video_play2 `div.video_right > div.video_img > a > img.video_play2`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.tj > div.div_title > p > img `div.tj > div.div_title > p > img`
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`
div.Rightfixed > div.RF_box > a > img `div.Rightfixed > div.RF_box > a > img`
div.container > div.Rightfixed > div.RF_box > img `div.container > div.Rightfixed > div.RF_box > img`
div.boxcenter > div.foot_txt > p > img `div.boxcenter > div.foot_txt > p > img`
li > span#_span_jiucuo > a > img `li > span#_span_jiucuo > a > img`
li > span#_ideConac > a > img#imgConac `li > span#_ideConac > a > img#imgConac`

Adding discernable and accessible text to input buttons may help screen reader users understand the purpose of the input button. Learn more about input buttons.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.container > div.top_r > div.search > input#sub-pc `div.container > div.top_r > div.search > input#sub-pc`

Form elements without effective labels can create frustrating experiences for screen reader users. Learn more about the `select` element.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
新闻媒体人民网新华网光明网央视网中国经济网中国网新浪网搜狐网科学网 `body > div.container > div.row > select`
政府机构和组织中国政府网国家发展改革委教育部科技部工业和信息化部财政部中国工程院国家自然科学基金委中国科协 `body > div.container > div.row > select`
国内院校清华大学北京大学中国科学技术大学中国科学院大学浙江大学上海交通大学南京大学复旦大学中山大学华中科技大学武汉大学上海科技大学 `body > div.container > div.row > select.mar0_pad`
国内科研机构林科院地科院水科院农科院医科院铁科院军科院 `body > div.container > div.row > select`
国际科研机构美国国家科学院美国国家科学基金委德国马普学会德国洪堡基金会德国弗朗霍夫学会德意志研究联合会法国国家科研中心法国原子能总署法兰西科… `body > div.container > div.row > select`
国际组织联合国教科文组织 “一带一路”国际科学组织联盟联合国培训和研究机构世界知识产权组织世界银行经济发展论坛亚太经合组织世界卫生组织世界粮食计… `body > div.container > div.row > select.mar0`

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
body > div.top2 > div.container > a.xsdlogotop `body > div.top2 > div.container > a.xsdlogotop`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a `div#swiper_container_top_Focus > ul.swiper-wrapper > li.swiper-slide > a`
div.row_left > div.divBox > div.zt > a `div.row_left > div.divBox > div.zt > a`
div.row_left > div.divBox > div.zt > a `div.row_left > div.divBox > div.zt > a`
div.row_left > div.divBox > div.zt > a.mar0 `div.row_left > div.divBox > div.zt > a.mar0`
div.row_right > ul.videoBox > li.hvr-grow-img > a `div.row_right > ul.videoBox > li.hvr-grow-img > a`
div.container > div.Rightfixed > div.RF_box > a `div.container > div.Rightfixed > div.RF_box > a`
div.foot_img > li > span#_span_jiucuo > a `div.foot_img > li > span#_span_jiucuo > a`
div.foot_img > li > span#_ideConac > a `div.foot_img > li > span#_ideConac > a`

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Tables and lists

Screen readers require list items (`<li>`) to be contained within a parent `<ul>`, `<ol>` or `<menu>` to be announced properly. Learn more about proper list structure.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.foot > div.boxcenter > div.foot_img > li `div.foot > div.boxcenter > div.foot_img > li`
div.foot > div.boxcenter > div.foot_img > li `div.foot > div.boxcenter > div.foot_img > li`

These are opportunities to improve the experience of reading tabular or list data using assistive technology, like a screen reader.

Best practices

Disabling zooming is problematic for users with low vision who rely on screen magnification to properly see the contents of a web page. Learn more about the viewport meta tag.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
body > meta `body > meta`

One main landmark helps screen reader users navigate a web page. Learn more about landmarks.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
html `html`

These items highlight common accessibility best practices.

Navigation

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
按回车键在新窗口打开无障碍说明页面,按Ctrl+~键打开导盲模式。 `body > a#esdTipLink1`

These are opportunities to improve keyboard navigation in your application.

○Interactive controls are keyboard focusable

○Interactive elements indicate their purpose and state

○The page has a logical tab order

○Visual order on the page follows DOM order

○User focus is not accidentally trapped in a region

○The user's focus is directed to new content added to the page

○HTML5 landmark elements are used to improve navigation

○Offscreen content is hidden from assistive technology

○Custom controls have associated labels

○Custom controls have ARIA roles

●`[aria-*]` attributes match their roles

●`[aria-hidden="true"]` is not present on the document `<body>`

●`[aria-*]` attributes have valid values

●`[aria-*]` attributes are valid and not misspelled

●Form elements have associated labels

●ARIA attributes are used as specified for the element's role

●Elements use only permitted ARIA attributes

●Document has a `<title>` element

●Links are distinguishable without relying on color.

●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).

●Touch targets have sufficient size and spacing.

●Heading elements appear in a sequentially-descending order

○`[accesskey]` values are unique

○`button`, `link`, and `menuitem` elements have accessible names

○Deprecated ARIA roles were not used

○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.

○`[aria-hidden="true"]` elements do not contain focusable descendents

○ARIA input fields have accessible names

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○`[role]`s have all required `[aria-*]` attributes

○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.

○`[role]`s are contained by their required parent element

○`[role]` values are valid

○Elements with the `role=text` attribute do not have focusable descendents.

○ARIA toggle fields have accessible names

○ARIA `tooltip` elements have accessible names

○ARIA `treeitem` elements have accessible names

○Buttons have an accessible name

○The page contains a heading, skip link, or landmark region

○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.

○Definition list items are wrapped in `<dl>` elements

○ARIA IDs are unique

○No form fields have multiple labels

○`<frame>` or `<iframe>` elements have a title

○`<html>` element has a valid value for its `[lang]` attribute

○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.

○`<input type="image">` elements have `[alt]` text

○The document does not use `<meta http-equiv="refresh">`

○`<object>` elements have alternate text

○Skip links are focusable.

○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.

○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.

○`[lang]` attributes have a valid value

○`<video>` elements contain a `<track>` element with `[kind="captions"]`

○Tables have different content in the summary attribute and `<caption>`.

○All heading elements contain content.

○Uses ARIA roles only on compatible elements

○Image elements do not have `[alt]` attributes that are redundant text.

○Identical links have the same purpose.

○Elements with visible text labels have matching accessible names.

○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.

○`<td>` elements in a large `<table>` have one or more table headers.

Best Practices

Trust and Safety

Why this matters

Performance issues directly impact user engagement and conversion rates.

Insecure URL	Request Resolution
www.cas.cn/	Allowed

User Experience

Image display dimensions should match natural aspect ratio. Learn more about image aspect ratio.

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Aspect Ratio (Displayed)	Aspect Ratio (Actual)
div.tab_con > div.yw_img > a > img.hvr-grow `div.tab_con > div.yw_img > a > img.hvr-grow`	www.cas.cn/yw/202604/W020260414668107692283_ORIGIN.jpg	216 x 146 (1.48)	600 x 400 (1.50)
ul.tzgg > li > a > img `ul.tzgg > li > a > img`	www.cas.cn/images/20230731zcjd.jpg	100 x 200 (0.50)	700 x 200 (3.50)
div.model_box > div.model_top > a > img `div.model_box > div.model_top > a > img`	www.cas.cn/cg/112072/images/P020190929620050824644.jpg	100 x 85 (1.18)	1220 x 85 (14.35)

General

Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Deprecation / Warning	Source
Specifying overflow: visible on img, video and canvas tags may cause them to produce visual content outside of the element bounds. See https://github.com/WICG/shared-element-transitions/blob/main/debugging_overflow_on_images.md.	www.cas.cn/

●Avoids third-party cookies

●Allows users to paste into input fields

●Avoids requesting the geolocation permission on page load

●Avoids requesting the notification permission on page load

●Serves images with appropriate resolution

●Page has the HTML doctype

●Properly defines charset

●No browser errors logged to the console

●No issues in the `Issues` panel in Chrome Devtools

●Ensure CSP is effective against XSS attacks

●Use a strong HSTS policy

●Ensure proper origin isolation with COOP

●Mitigate clickjacking with XFO or CSP

●Mitigate DOM-based XSS with Trusted Types

●Detected JavaScript libraries

●Page has valid source maps

○Redirects HTTP traffic to HTTPS

SEO

Content Best Practices

Meta descriptions may be included in search results to concisely summarize page content. Learn more about the meta description.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.top2 > div.container > a.xsdlogotop > img.logo `div.top2 > div.container > a.xsdlogotop > img.logo`
div.top2 > div.container > a.xsdlogotop > img.logobtmxsd `div.top2 > div.container > a.xsdlogotop > img.logobtmxsd`
div.top2 > div.container > div.xsdadd-2025 > img.xsdimg01 `div.top2 > div.container > div.xsdadd-2025 > img.xsdimg01`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc `ul.swiper-wrapper > li.swiper-slide > a > img.focus_img_pc`
ul.tab_title > li.tab_title_yw1 > a > img `ul.tab_title > li.tab_title_yw1 > a > img`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
div.tab_con > div.yw_img > a > img.hvr-grow `div.tab_con > div.yw_img > a > img.hvr-grow`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.tab_con > div.ky_img > a > img.hvr-grow `div.tab_con > div.ky_img > a > img.hvr-grow`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.tab_con > div.ky_img > a > img.hvr-grow `div.tab_con > div.ky_img > a > img.hvr-grow`
div.divBox > div.div_title > p > img `div.divBox > div.div_title > p > img`
div.divBox > div.zt > a > img.hvr-grow `div.divBox > div.zt > a > img.hvr-grow`
div.divBox > div.zt > a > img.hvr-grow `div.divBox > div.zt > a > img.hvr-grow`
div.divBox > div.zt > a.mar0 > img.hvr-grow `div.divBox > div.zt > a.mar0 > img.hvr-grow`
div.divBox > div.jl > div.jl_left > img `div.divBox > div.jl > div.jl_left > img`
ul.videoBox > li.hvr-grow-img > a > img `ul.videoBox > li.hvr-grow-img > a > img`
ul.videoBox > li.hvr-grow-img > a > img.hvr-grow `ul.videoBox > li.hvr-grow-img > a > img.hvr-grow`
ul.videoBox > li.hvr-grow-img > a > img.hvr-grow `ul.videoBox > li.hvr-grow-img > a > img.hvr-grow`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.tab_con > div.video_left > a > img `div.tab_con > div.video_left > a > img`
div.tab_con > div.video_left > a > img.video_play2 `div.tab_con > div.video_left > a > img.video_play2`
div.video_right > div.video_img > a > img `div.video_right > div.video_img > a > img`
div.video_right > div.video_img > a > img.video_play2 `div.video_right > div.video_img > a > img.video_play2`
div.video_right > div.video_img > a > img `div.video_right > div.video_img > a > img`
div.video_right > div.video_img > a > img.video_play2 `div.video_right > div.video_img > a > img.video_play2`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
ul.tab_title > li.now > a > img `ul.tab_title > li.now > a > img`
ul.tab_title > li > a > img `ul.tab_title > li > a > img`
div.tj > div.div_title > p > img `div.tj > div.div_title > p > img`
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`
ul.tj_list > li.hvr-grow-img > a > img `ul.tj_list > li.hvr-grow-img > a > img`
div.Rightfixed > div.RF_box > a > img `div.Rightfixed > div.RF_box > a > img`
div.container > div.Rightfixed > div.RF_box > img `div.container > div.Rightfixed > div.RF_box > img`
div.boxcenter > div.foot_txt > p > img `div.boxcenter > div.foot_txt > p > img`
li > span#_span_jiucuo > a > img `li > span#_span_jiucuo > a > img`
li > span#_ideConac > a > img#imgConac `li > span#_ideConac > a > img#imgConac`

Format your HTML in a way that enables crawlers to better understand your app’s content.

Crawling and Indexing

Why this matters

Performance issues directly impact user engagement and conversion rates.

Uncrawlable Link
无障碍 `div.container > div.top_r > div.top_link > a#toolbarSwitch`
div.top2 > div.container > div.top_link_m > a#toolbarSwitchmob `div.top2 > div.container > div.top_link_m > a#toolbarSwitchmob`
按回车键在新窗口打开无障碍说明页面,按Ctrl+~键打开导盲模式。 `body > a#esdTipLink1`
.cls-1{fill:#fff;} `div.cy_toolbar_bg_table > ul > li#cy_refrash > a#toolbar_refresh`
.st0{fill:none;stroke:#FFFFFF;stroke-width:1.3;stroke-linecap:round;stroke-line… `div.cy_toolbar_bg_table > ul > li#cy_playSpeech > a#toolbar_speakVolume`
.cls-1{fill:#fff;} `div.cy_toolbar_bg_table > ul > li#cy_pointerRead > a#toolbar_speakSpeed`
.cls-1{fill:#fff;} `div.cy_toolbar_bg_table > ul > li#cy_pointerRead > a#toolbar_readChange`
.cls-1{fill:#fff;} `div.cy_toolbar_bg_table > ul > li#cy_color > a#toolbar_colorChange`
.cls-1{fill:#fff;} `div.cy_toolbar_bg_table > ul > li#cy_bigword > a#toolbar_pageZoomIc`
.cls-1{fill:#fff;} `div.cy_toolbar_bg_table > ul > li#cy_smallword > a#toolbar_pageZoomDc`
.cls-1{fill:#fff;} `div.cy_toolbar_bg_table > ul > li#cy_arrow > a#toolbar_refresh1`
.cls-1{fill:#fff;} `div.cy_toolbar_bg_table > ul > li#cy_ruler > a#toolbar_guides`
.cls-1{fill:#fff;} `div.cy_toolbar_bg_table > ul > li#cy_displayScreen > a#toolbar_magnifier`
.st0{fill:none;stroke:#FFFFFF;stroke-width:1.3;stroke-linecap:round;stroke-line… `div.cy_toolbar_bg_table > ul > li#cy_pinned > a#toolbar_pinned`
.cls-1{fill:#fff;} `div.cy_toolbar_bg_table > ul > li#cy_more > a#toolbar_more`
.cls-1{fill:#fff;} `div.cy_toolbar_bg_table > ul > li#cy_move > a#toNav`
.cls-1{fill:#fff;} `div.cy_toolbar_bg_table > ul > li#cy_close > a#toolbar_exit`
.st0{fill:none;stroke:#FFFFFF;stroke-width:1.3;stroke-linecap:round;stroke-line… `div#toolbarPage2content > div#otherBtns > div#cy_playSpeech_2 > a#toolbar_speakOnOff`
.cls-1{fill:#fff;} `div#toolbarPage2content > div#otherBtns > div.readDiv > a#toolbar_help_move`
.cls-1{fill:#fff;} `div#toolbarPage2content > div#otherBtns > div.readDiv > a#toolbar_magnifier_2`
.cls-1{fill:#fff;} `div#toolbarPage2content > div#otherBtns > div.readDiv > a#toFirstPage`
.cls-1{fill:#fff;} `div#toolbarPage2content > div#otherBtns > div.readDiv > a#toolbar_exit2`

To appear in search results, crawlers need access to your app.

○Structured data is valid

●Page isn’t blocked from indexing

●Document has a `<title>` element

●Page has successful HTTP status code

●Links have descriptive text

●Document has a valid `hreflang`

○robots.txt is valid

○Document has a valid `rel=canonical`

Results for https://cas.cn

Site Health

How you compare

Top Priorities (5)

Fix Priority Matrix

Quick Wins

Strategic

Easy Improvements

Deprioritize

What fixing these means

Conversion Barriers

Speed (1)

Trust (2)

Usability (2)

Content (2)

Navigation (3)

Return on Investment

Investment

Monthly returns

Regulatory risk avoided

Payback period

Estimated Remediation Cost

Cost by category

Cost by effort level

What Inaction Is Costing You

Compliance Risk

Bandwidth Waste

Lighthouse Scores

Core Web Vitals

Detailed Report

Performance

Insights

Diagnostics

Accessibility

Contrast

Internationalization and localization

Names and labels

Tables and lists

Best practices

Navigation

Best Practices

Trust and Safety

User Experience

General

SEO

Content Best Practices

Crawling and Indexing

Lighthouse Scores

Core Web Vitals

Detailed Report

Performance

Insights

Diagnostics

Accessibility

Contrast

Internationalization and localization

Names and labels

Tables and lists

Best practices

Navigation

Best Practices

Trust and Safety

User Experience

General

SEO

Content Best Practices

Crawling and Indexing

Keyboard Shortcuts