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· 0 checks — Desktop Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.
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Detailed Report

Audit breakdown by category with detailed findings.

85

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

Performance issues directly impact user engagement and conversion rates.

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.

RequestCache TTLTransfer Size
www.ocn.ne.jp/top_tools/center/upper_info_slide/images/700x308_ahamo_202511.png0.0 ms400.6 KiB
www.ocn.ne.jp/top_tools/center/upper_info_slide/images/260401_2_mini_700x308.jpg0.0 ms367.2 KiB
www.ocn.ne.jp/top_tools/center/campaign_info/images/260401_2_max_700x308.jpg0.0 ms325.7 KiB
/top_tools/center/upper_info_slide/images/260401_2_ahamo_...0.0 ms315.7 KiB
/top_tools/center/campaign_info/images/260407_mini_max-us...0.0 ms187.9 KiB
/top_tools/center/campaign_info/images/260417_dpoint_gian...0.0 ms174.5 KiB
www.ocn.ne.jp/top_tools/center/prod_denkigas/images/denki_700x308_20260401.png0.0 ms170.7 KiB
/top_tools/center/campaign_info/images/260407_ahamo-used_...0.0 ms159.3 KiB
www.ocn.ne.jp/ocn_assets/pc/img/241101_docomo_rgb_slogan_logo.png0.0 ms117.3 KiB
/top_tools/center/upper_info_slide/images/700x308px_hikar...0.0 ms80.6 KiB
/top_tools/center/upper_info_slide/images/700x308_tokuten...0.0 ms65.8 KiB
www.ocn.ne.jp/top_tools/center/prod_denkigas/images/gas_700x308_260401.png0.0 ms39.3 KiB
www.ocn.ne.jp/ocn_assets/pc/img/left_bottom_banner/banner_336_280-dlpa.jpg0.0 ms32.7 KiB
/ocn_assets/pc/js/jquery-1.6.2.min.js?id=a1a8cb16a060f628...0.0 ms31.8 KiB
www.ocn.ne.jp/top_tools/center/campaign_info/images/260401_point_700x308.png0.0 ms30.0 KiB
www.ocn.ne.jp/ocn_assets/pc/js/swiper.min.js?id=cabdd76e521b31cec9589102858f42e30.0 ms29.4 KiB
www.ocn.ne.jp/ocn_assets/pc/img/new_sprite.png?202012100.0 ms29.1 KiB
www.ocn.ne.jp/ocn_assets/pc/img/left_bottom_banner/bohankyoshitsu2nd.jpg0.0 ms26.8 KiB
www.ocn.ne.jp/ocn_assets/pc/css/base3.css?id=dbf4136cc34c1a98b72e4520e28fbf160.0 ms22.6 KiB
/ocn_assets/pc/img/left_bottom_banner/stopkaizokuban2022_...0.0 ms21.4 KiB
www.ocn.ne.jp/top_tools/left/left_top_banner/images/ocntop_215-80_c-202603.png0.0 ms18.0 KiB
www.ocn.ne.jp/ocn_assets/pc/js/ocntop.js?id=1818ceb7749627ade8698a0af03dfafe0.0 ms12.6 KiB
/top_tools/center/online_shop/images/cp3724_hikari_124x87...0.0 ms9.8 KiB
www.ocn.ne.jp/top_tools/center/online_shop/images/img_ocnTop_02_251203.jpg0.0 ms9.8 KiB
www.ocn.ne.jp/ocn_assets/pc/img/dmenu/icon-transfer.png0.0 ms9.6 KiB
/top_tools/center/online_shop/images/img_ocnTop_01_250401...0.0 ms8.7 KiB
www.ocn.ne.jp/ocn_assets/pc/img/dmenu/icon-kuji.png0.0 ms7.5 KiB
www.ocn.ne.jp/ocn_assets/pc/img/dmenu/icon-sports.png0.0 ms7.1 KiB
/top_tools/center/prod_internet_banner/images/ocnint_logo...0.0 ms6.5 KiB
/top_tools/center/prod_internet_banner/images/500x220px_a...0.0 ms6.4 KiB
www.ocn.ne.jp/ocn_assets/pc/img/dmenu/icon-fortune.png0.0 ms6.1 KiB
www.ocn.ne.jp/ocn_assets/pc/img/new_header_sprite.png?2312010.0 ms5.8 KiB
www.ocn.ne.jp/ocn_assets/pc/img/dmenu/icon-search.png0.0 ms5.3 KiB
www.ocn.ne.jp/ocn_assets/pc/img/dmenu/icon-weather.png0.0 ms3.9 KiB
www.ocn.ne.jp/ocn_assets/pc/img/dmenu/icon-dpoint.png0.0 ms3.9 KiB
www.ocn.ne.jp/ocn_assets/pc/img/dmenu/icon-news.png0.0 ms3.4 KiB
/ocn_assets/pc/css/swiper.min.css?id=2603e9c21c62042a0e96...0.0 ms3.0 KiB
www.ocn.ne.jp/ocn_assets/pc/img/4_header_ocn.gif0.0 ms3.0 KiB
/ocn_assets/pc/js/jquery.lazyload.min.js?id=5c01d7aff077b...0.0 ms1.6 KiB
www.ocn.ne.jp/ocn_assets/pc/img/icon-sv-info.png0.0 ms782 B
www.ocn.ne.jp/ocn_assets/pc/img/icon-sv-mypage.png0.0 ms720 B
www.ocn.ne.jp/ocn_assets/pc/img/icon-sv-support.png0.0 ms698 B
/v.gif?cd=0&a=377405&d=ocn.ne.jp&u=D267F3E29DD0BBC9F06510...43200.0 s145 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.

A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:source label:Top function call valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:227.54 source:map[column:14897 line:16 type:source-location url:https://www.ocn.ne.jp/ocn_assets/pc/js/jquery-1.6.2.min.js?id=a1a8cb16a060f6280a767187fd22e037 urlProvider:network]]]
headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:222.735 source:map[column:5090 line:17 type:source-location url:https://www.ocn.ne.jp/ocn_assets/pc/js/jquery-1.6.2.min.js?id=a1a8cb16a060f6280a767187fd22e037 urlProvider:network]] map[reflowTime:2.195 source:map[column:16267 line:11 type:source-location url:https://www.ocn.ne.jp/ocn_assets/pc/js/swiper.min.js?id=cabdd76e521b31cec9589102858f42e3 urlProvider:network]] map[reflowTime:1.713 source:map[column:20341 line:11 type:source-location url:https://www.ocn.ne.jp/ocn_assets/pc/js/swiper.min.js?id=cabdd76e521b31cec9589102858f42e3 urlProvider:network]] map[reflowTime:0.685 source:map[column:6682 line:11 type:source-location url:https://www.ocn.ne.jp/ocn_assets/pc/js/swiper.min.js?id=cabdd76e521b31cec9589102858f42e3 urlProvider:network]] map[reflowTime:0.212 source:map[column:5811 line:11 type:source-location url:https://www.ocn.ne.jp/ocn_assets/pc/js/swiper.min.js?id=cabdd76e521b31cec9589102858f42e3 urlProvider:network]]]

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.

URLResource SizeEst Savings
【ahamo光＋ahamo】速さ・容量・コストもう我慢しない。超高速10Gbps ahamo光 最初の6か月間月額500円（税込）。たっぷり30GB aham… div.swiper-slide > div.infoSlideItem > a#inpr-slider3-12 > img
www.ocn.ne.jp/top_tools/center/upper_info_slide/images/700x308_ahamo_202511.png399.8 KiB378.1 KiB
ドコモオンラインショップでOCN モバイル ONEからドコモ miniへ移行しておトクにスマホを購入しよう！ div.swiper-slide > div.infoSlideItem > a#inpr-slider3-15 > img
www.ocn.ne.jp/top_tools/center/upper_info_slide/images/260401_2_mini_700x308.jpg366.5 KiB344.8 KiB
ドコモオンラインショップでOCN モバイル ONEからドコモ MAXへ移行しておトクにスマホを購入しよう！ div.swiper-slide > div.campaignItem > a#inpr-slider2-13 > img
www.ocn.ne.jp/top_tools/center/campaign_info/images/260401_2_max_700x308.jpg325.0 KiB316.3 KiB
ahamoサイトでOCN モバイル ONEからahamoへ移行しておトクにスマホを購入しよう！ div.swiper-slide > div.infoSlideItem > a#inpr-slider3-14 > img
/top_tools/center/upper_info_slide/images/260401_2_ahamo_...315.0 KiB293.3 KiB
ドコモオンラインショップでOCN モバイル ONEからドコモ mini＆MAXへ移行しておトクに中古端末を購入しよう！ div.swiper-slide > div.campaignItem > a#inpr-slider2-15 > img
/top_tools/center/campaign_info/images/260407_mini_max-us...187.3 KiB178.7 KiB
ドコモでんき li.prodPlansItem > div.prodPlans > a.prodPlansLink > img
www.ocn.ne.jp/top_tools/center/prod_denkigas/images/denki_700x308_20260401.png170.2 KiB167.3 KiB
巨人戦観戦フルコースがあたる div.swiper-slide > div.campaignItem > a#inpr-slider2-11 > img
/top_tools/center/campaign_info/images/260417_dpoint_gian...174.0 KiB165.3 KiB
ahamoサイトでOCN モバイル ONEからahamoへ移行しておトクに中古スマホを購入しよう！ div.swiper-slide > div.campaignItem > a#inpr-slider2-14 > img
/top_tools/center/campaign_info/images/260407_ahamo-used_...158.7 KiB150.1 KiB
つなごう。驚きを。幸せを。 NTT DOCOMO div#minWidth > div#footer > div#corpraitinfo > img.ci
www.ocn.ne.jp/ocn_assets/pc/img/241101_docomo_rgb_slogan_logo.png116.8 KiB116.7 KiB
【ドコモ mini ＋ ドコモ光】ネットとスマホの月額料金最大6か月間月々1,380円（税込）で利用可能！ div.swiper-slide > div.infoSlideItem > a#inpr-slider3-13 > img
/top_tools/center/upper_info_slide/images/700x308px_hikar...80.2 KiB58.5 KiB
OCN インターネット公式サイトから「ドコモ光」お申込みで現金還元！10ギガ 55,000円 or 1ギガ 37,000円 ＋ 他社からのお乗り換えでdポイン… div.swiper-slide > div.infoSlideItem > a#inpr-slider3-11 > img
/top_tools/center/upper_info_slide/images/700x308_tokuten...65.4 KiB43.7 KiB
ドコモ ガス li.prodPlansItem > div.prodPlans > a.prodPlansLink > img
www.ocn.ne.jp/top_tools/center/prod_denkigas/images/gas_700x308_260401.png38.9 KiB36.1 KiB
Wi-Fiルーターを買い替えてセキュリティと快適さをアップ！ div#lcol > div.banner > a#b-rbnr-3 > img
www.ocn.ne.jp/ocn_assets/pc/img/left_bottom_banner/banner_336_280-dlpa.jpg32.4 KiB26.1 KiB
メグたんのログインアンケート div.swiper-slide > div.campaignItem > a#inpr-slider2-12 > img
www.ocn.ne.jp/top_tools/center/campaign_info/images/260401_point_700x308.png29.6 KiB22.3 KiB
「ストップ・オレオレ詐欺４７～家族の絆作戦～」プロジェクトチーム(ＳＯＳ４７) div#lcol > div.banner > a#b-rbnr-1 > img
www.ocn.ne.jp/ocn_assets/pc/img/left_bottom_banner/bohankyoshitsu2nd.jpg26.5 KiB22.2 KiB
STOP！海賊版 div#lcol > div.banner > a#b-rbnr-2 > img
/ocn_assets/pc/img/left_bottom_banner/stopkaizokuban2022_...21.1 KiB17.3 KiB
OCN インターネット×ドコモ光 10ギガ新規お申込みで最大55,000円現金還元 div#lcol > div.banner > a#m-upleftbnr-1 > img
www.ocn.ne.jp/top_tools/left/left_top_banner/images/ocntop_215-80_c-202603.png17.7 KiB14.9 KiB
ul.dmenuList > li > a#d-menu-16 > img ul.dmenuList > li > a#d-menu-16 > img
www.ocn.ne.jp/ocn_assets/pc/img/dmenu/icon-transfer.png9.2 KiB8.7 KiB
OCN Internet × ドコモ光 div.cont > div#digitalstorebox > a#c-store-31 > img
/top_tools/center/online_shop/images/cp3724_hikari_124x87...9.4 KiB7.8 KiB
27E1N1800A/11 div.cont > div#digitalstorebox > a#c-store-21 > img
www.ocn.ne.jp/top_tools/center/online_shop/images/img_ocnTop_02_251203.jpg9.4 KiB7.7 KiB
ul.dmenuList > li > a#d-menu-19 > img ul.dmenuList > li > a#d-menu-19 > img
www.ocn.ne.jp/ocn_assets/pc/img/dmenu/icon-kuji.png7.2 KiB6.7 KiB
HD-NRLD4.0U3-BA div.cont > div#digitalstorebox > a#c-store-11 > img
/top_tools/center/online_shop/images/img_ocnTop_01_250401...8.3 KiB6.6 KiB
ul.dmenuList > li > a#d-menu-13 > img ul.dmenuList > li > a#d-menu-13 > img
www.ocn.ne.jp/ocn_assets/pc/img/dmenu/icon-sports.png6.8 KiB6.3 KiB
ul.dmenuList > li > a#d-menu-15 > img ul.dmenuList > li > a#d-menu-15 > img
www.ocn.ne.jp/ocn_assets/pc/img/dmenu/icon-fortune.png5.8 KiB5.3 KiB
ahamo光＋ahamo div.prodPickup > div.prodPickupImg > a > img
/top_tools/center/prod_internet_banner/images/500x220px_a...6.1 KiB4.9 KiB

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-25-IMG
nodeLabel: OCN インターネット公式サイトから「ドコモ光」お申込みで現金還元！10ギガ 55,000円 or 1ギガ 37,000円 ＋ 他社からのお乗り換えでdポイン…
path: 1,HTML,1,BODY,0,DIV,0,DIV,0,DIV,1,DIV,0,DIV,0,DIV,1,DIV,0,DIV,5,DIV,0,DIV,0,A,0,IMG
selector: div.swiper-slide > div.infoSlideItem > a#inpr-slider3-11 > img
snippet: <img width="550" height="242" alt="OCN インターネット公式サイトから「ドコモ光」お申込みで現金還元！10ギガ 55,000円 or 1ギガ 37,000円 ＋ 他社からのお乗り換え…" src="/top_tools/center/upper_info_slide/images/700x308_tokuten_202512.png">

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.

URLTransfer Size
www.ocn.ne.jp/ocn_assets/pc/css/base3.css?id=dbf4136cc34c1a98b72e4520e28fbf1622.6 KiB
/ocn_assets/pc/js/jquery-1.6.2.min.js?id=a1a8cb16a060f628...31.8 KiB
www.ocn.ne.jp/ocn_assets/pc/js/swiper.min.js?id=cabdd76e521b31cec9589102858f42e329.4 KiB
/ocn_assets/pc/js/jquery.lazyload.min.js?id=5c01d7aff077b...1.6 KiB
www.ocn.ne.jp/ocn_assets/pc/js/ocntop.js?id=1818ceb7749627ade8698a0af03dfafe12.6 KiB
/ocn_assets/pc/css/swiper.min.css?id=2603e9c21c62042a0e96...3.0 KiB

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: 316 ms
URLTime Spent
ocn.ne.jp/316 ms
www.ocn.ne.jp/0.0 ms

Keep the server response time for the main document short because all other requests depend on it. Learn more about the Time to First Byte metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 570 ms
URLTime Spent
www.ocn.ne.jp/670 ms

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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

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

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 40 ms 337.3 KiB
URLTransfer SizeEst Savings
www.googletagmanager.com/gtag/js?id=G-2VYT9C383M&cx=c&gtm=4e64h1150.8 KiB75.0 KiB
www.googletagmanager.com/gtag/js?id=G-5XDKHMB5SV&cx=c&gtm=4e64h1143.5 KiB73.5 KiB
www.googletagmanager.com/gtag/js?id=G-2750JE9XQG&cx=c&gtm=4e64h1150.9 KiB64.7 KiB
www.googletagmanager.com/gtm.js?id=GTM-WQ8B89G&gtm=4e64h1133.0 KiB64.0 KiB
www.googletagmanager.com/gtm.js?id=GTM-KK5LPR132.7 KiB60.1 KiB

Many navigations are performed by going back to a previous page, or forwards again. The back/forward cache (bfcache) can speed up these return navigations. Learn more about the bfcache

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failure reasonFailure type
Pages with cache-control:no-store header cannot enter back/forward cache.Actionable
Pages whose main resource has cache-control:no-store cannot enter back/forward cache.Not actionable
Back/forward cache is disabled because some JavaScript network request received resource with Cache-Control: no-store header.Not actionable

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: 0.0 ms 17.5 KiB
URLTransfer SizeEst Savings
www.ocn.ne.jp/ocn_assets/pc/css/base3.css?id=dbf4136cc34c1a98b72e4520e28fbf1622.3 KiB17.5 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.

URLTransfer Size
www.ocn.ne.jp/top_tools/center/upper_info_slide/images/700x308_ahamo_202511.png400.6 KiB
www.ocn.ne.jp/top_tools/center/upper_info_slide/images/260401_2_mini_700x308.jpg367.2 KiB
www.ocn.ne.jp/top_tools/center/campaign_info/images/260401_2_max_700x308.jpg325.7 KiB
/top_tools/center/upper_info_slide/images/260401_2_ahamo_...315.7 KiB
/top_tools/center/campaign_info/images/260407_mini_max-us...187.9 KiB
/top_tools/center/campaign_info/images/260417_dpoint_gian...174.5 KiB
www.ocn.ne.jp/top_tools/center/prod_denkigas/images/denki_700x308_20260401.png170.7 KiB
/top_tools/center/campaign_info/images/260407_ahamo-used_...159.3 KiB
www.googletagmanager.com/gtag/js?id=G-2750JE9XQG&cx=c&gtm=4e64h1150.9 KiB
www.googletagmanager.com/gtag/js?id=G-2VYT9C383M&cx=c&gtm=4e64h1150.8 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
つなごう。驚きを。幸せを。 NTT DOCOMO div#minWidth > div#footer > div#corpraitinfo > img.ci
www.ocn.ne.jp/ocn_assets/pc/img/241101_docomo_rgb_slogan_logo.png
Wi-Fiルーターを買い替えてセキュリティと快適さをアップ！ div#lcol > div.banner > a#b-rbnr-3 > img
www.ocn.ne.jp/ocn_assets/pc/img/left_bottom_banner/banner_336_280-dlpa.jpg
「ストップ・オレオレ詐欺４７～家族の絆作戦～」プロジェクトチーム(ＳＯＳ４７) div#lcol > div.banner > a#b-rbnr-1 > img
www.ocn.ne.jp/ocn_assets/pc/img/left_bottom_banner/bohankyoshitsu2nd.jpg
STOP！海賊版 div#lcol > div.banner > a#b-rbnr-2 > img
/ocn_assets/pc/img/left_bottom_banner/stopkaizokuban2022_...
OCN インターネット×ドコモ光 10ギガ新規お申込みで最大55,000円現金還元 div#lcol > div.banner > a#m-upleftbnr-1 > img
www.ocn.ne.jp/top_tools/left/left_top_banner/images/ocntop_215-80_c-202603.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
●LCP breakdown
●Modern HTTP
●Optimize viewport for mobile
●Minify CSS
●Minify JavaScript
●User Timing marks and measures 5 user timings
●JavaScript execution time 0.4 s
●Minimizes main-thread work 0.9 s
●Avoid long main-thread tasks 4 long tasks found
●Network Requests
●Network Round Trip Times 20 ms
●Server Backend Latencies 110 ms
●Tasks
●Diagnostics
●Metrics
●Screenshot Thumbnails
●Final Screenshot
●Script Treemap Data
●Resources Summary
○INP breakdown
○Avoid non-composited animations
○Avoid large layout shifts
97

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.

Best practices

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.

○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-hidden="true"]` is not present on the document `<body>`
●Image elements have `[alt]` attributes
●Background and foreground colors have a sufficient contrast ratio
●`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
●Definition list items are wrapped in `<dl>` elements
●Document has a `<title>` element
●`<html>` element has a `[lang]` attribute
●`<html>` element has a valid value for its `[lang]` attribute
●Links have a discernible name
●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements
●Touch targets have sufficient size and spacing.
●Heading elements appear in a sequentially-descending order
●Identical links have the same purpose.
○`[accesskey]` values are unique
○`[aria-*]` attributes match their roles
○`button`, `link`, and `menuitem` elements have accessible names
○ARIA attributes are used as specified for the element's role
○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
○Elements use only permitted ARIA attributes
○`[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
○`[aria-*]` attributes have valid values
○`[aria-*]` attributes are valid and not misspelled
○Buttons have an accessible name
○The page contains a heading, skip link, or landmark region
○ARIA IDs are unique
○No form fields have multiple labels
○`<frame>` or `<iframe>` elements have a title
○`<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
○Links are distinguishable without relying on color.
○The document does not use `<meta http-equiv="refresh">`
○`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
○`<object>` elements have alternate text
○Select elements have associated label elements.
○Skip links are focusable.
○No element has a `[tabindex]` value greater than 0
○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.
○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.
96

Best Practices

Browser Compatibility

Specifying a doctype prevents the browser from switching to quirks-mode. Learn more about the doctype declaration.

Why this matters

Performance issues directly impact user engagement and conversion rates.

●Uses HTTPS
●Avoids deprecated APIs
●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
●Displays images with correct aspect ratio
●Serves images with appropriate resolution
●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
92

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.

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
会員のお客さま div#gnav > ul#gnavTabs > li.gnavTab > a
サービス一覧 div#gnav > ul#gnavTabs > li.gnavTab > a

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
●Document has a meta description
●Page has successful HTTP status code
●Links have descriptive text
●Image elements have `[alt]` attributes
●Document has a valid `hreflang`
●Document has a valid `rel=canonical`
○robots.txt is valid

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