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Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
73
GRADE
C
FIX
4
REVIEW
4
PASS
5
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
60
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
79
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
81
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
69
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

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

2.68 s

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

4.25 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.

0.029

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

4.60 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.

4.26 s

Page Load Progression

919 ms
1.8 s
2.8 s
3.7 s
4.6 s
5.5 s
6.4 s
7.3 s
Checks
15
5 PASS 4 REVIEW 4 FIX
F
Page Weight Budget
Action
4.7 MB transferred, 54 requests
FIX
4.7 MB transferred, 54 requests
Critical::
Page weighs 5.1 MB (4.7 MB transferred)
Warning::
Images are 4.3 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 4.3 MB
Info::
54 HTTP requests
Info::
Estimated 0.98 g CO2 per page load
4.7 MB / 2.4 MB budget
4.7 MB transferred
54 requests
0.98 g CO2 per page load
Images 4.3 MiB 92%
JavaScript 177.4 KiB 4%
Fonts 111.0 KiB 2%
CSS 56.9 KiB 1%
HTML 20.3 KiB 0%
Other 4.9 KiB 0%
Other 1.3 KiB 0%
Other 120 B 0%
0 2.4 MB 4.9 MB
Over budget

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Why this matters

Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.

Source: web.dev

D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (4.7 MiB of 4.7 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
D
Page Weight Inventory
Action
54 resources · 4.7 MB · 77 KB savings available
FIX
54 resources · 4.7 MB · 77 KB savings available
Warning::
Page weight 3.7 MB over 1MB target
Got: 4.7 MB Expected: ≤ 1 MB
Info::
~77 KB of savings available
Warning::
53 third-party resources (100% of weight)
Info::
4 resources over 200KB
54 resources · 4.7 MiB · 53 third-party 3.7 MiB over 1MB target
Image 92% · 4.3 MiB
JavaScript 4% · 177.4 KiB
Font 2% · 111.0 KiB
CSS 1% · 56.9 KiB
Document 0% · 20.8 KiB
Other 0% · 1.4 KiB

~76.9 KiB of savings available

Remove unused JavaScript: 76.9 KiB
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
Image Optimization
Action
28 images, 0 KB saveable
REVIEW
28 images, 0 KB saveable
Warning::
https://www.bt.cn/static/astro/images/trust/hunan.... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.bt.cn/static/astro/images/trust/yanjiu... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.bt.cn/static/astro/images/home/step/in... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.bt.cn/static/astro/images/home/free-ic... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.bt.cn/static/astro/images/trust/fuli.p... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.bt.cn/static/astro/images/trust/xiehui... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.bt.cn/static/astro/images/trust/njsj.p... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.bt.cn/static/astro/images/home/step/do... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.bt.cn/static/astro/images/home/step/co... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.bt.cn/static/astro/images/home/step/pa... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
28 images 4.3 MB
0 oversized -0 KB
28 legacy format
10 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

B
JS Execution Cost
990ms total JS execution
REVIEW
990ms total JS execution
Warning::
https://www.bt.cn/new/index.html: 806ms CPU time
Info::
Unattributable: 111ms CPU time
Info::
https://scripts.clarity.ms/0.8.59/clarity.js: 72ms CPU time
Warning::
Third-party scripts: 990ms (100% of total)

Main Thread Breakdown

Other 32% Rendering 27% Style & Layout 26% Script Evaluation 14%
ScriptTotalScriptingParse/CompileParty
https://www.bt.cn/new/index.html806ms10ms1ms3rd
Unattributable111ms2ms0ms3rd
https://scripts.clarity.ms/0.8.59/clarity.js72ms62ms2ms3rd
B
JS Bundles
14 scripts, 77 KB unused
REVIEW
14 scripts, 77 KB unused
Warning::
https://www.bt.cn/static/astro/js/utils-vendor.js?...: 41 KB unused (69%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.bt.cn/static/astro/js/vue-vendor.js?ve...: 35 KB unused (92%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 77 KB
77 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.bt.cn/static/astro/js/utils-vendor.js?version=177682159361 KB41 KB (69%)✓3rd
https://www.bt.cn/static/astro/js/vue-vendor.js?version=177682159339 KB35 KB (92%)✓3rd
https://www.bt.cn/static/astro/js/StoryCarousel.astro_astro_type_script_index_0_lang.js?version=17768215933 KB—✓3rd
https://bat.bing.com/bat.js?version=177682159315 KB—✓3rd
https://bat.bing.com/p/action/97128650.js2 KB—✓3rd
https://www.clarity.ms/tag/uet/97128650?insights=11 KB—✓3rd
https://scripts.clarity.ms/0.8.59/clarity.js26 KB—✓3rd
https://www.bt.cn/static/astro/js/Layout.astro_astro_type_script_index_0_lang.js?version=17768215936 KB—✓3rd
https://www.bt.cn/static/astro/js/Header.astro_astro_type_script_index_0_lang.js?version=17768215931 KB—✓3rd
https://hm.baidu.com/hm.js?6e78ef648057d9f2ab12dcc287b440f620 KB—✓3rd

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
1 fonts (111 KB)
PASS
1 fonts (111 KB)
Info::
1 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

1

111 KB total

Render-blocking

0

of 1

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 1.0 s 2.0 s 3.0 s 4.0 s FCP 2.7 s LCP 4.3 shttps://www.bt.cn/static/astro/woff2/fa-solid-900.woff2fa-solid-900.woff2 https://www.bt.cn/static/astro/woff2/fa-solid-900.woff2 — 111.0 KiB — 580 ms — font-display: swap
fa-solid-900.woff2 woff2 swap
Size 111 KB
Load time 580 ms
Start 2.4 s
Risk FOUT — text flashes from fallback to web font
  • Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
Optimization checklist
  • Preload critical fonts (priority=high)
  • Use woff2 format for all fonts
  • Set font-display to swap, optional, or fallback
  • Subset large fonts (≤100 KB each)

Fixing the unchecked items could save ~55 KB and ~110 ms

A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
Network Waterfall
54 requests over 6660ms
INFO
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s 6.0 s FCP 2.7 s LCP 4.3 shttps://bt.cn// https://bt.cn/ — 302 — 107 B — 700 ms — h2https://www.bt.cn/www.bt.cn/ https://www.bt.cn/ — 302 — 321 B — 694 ms — h2https://www.bt.cn/new/index.htmlwww.bt.cn/new/index.html https://www.bt.cn/new/index.html — 200 — 20.3 KiB — 500 ms — h2https://bat.bing.com/bat.js?version=1776821593bat.bing.com/bat.js?version=1776821... https://bat.bing.com/bat.js?version=1776821593 — 200 — 15.5 KiB — 123 ms — h2https://hm.baidu.com/hm.js?6e78ef648057d9f2ab12dcc287b440f6hm.baidu.com/hm.js?6e78ef648057d9f2... https://hm.baidu.com/hm.js?6e78ef648057d9f2ab12dcc287b440f6 — 200 — 19.6 KiB — 841 ms — http/1.1https://www.bt.cn/static/astro/css/index.css?version=1776821593www.bt.cn/static/astro/css/index.cs... https://www.bt.cn/static/astro/css/index.css?version=1776821593 — 200 — 3.2 KiB — 217 ms — h2https://www.bt.cn/static/astro/css/1111-1.css?version=1776821593www.bt.cn/static/astro/css/1111-1.c... https://www.bt.cn/static/astro/css/1111-1.css?version=1776821593 — 200 — 53.6 KiB — 444 ms — h2https://www.bt.cn/static/astro/icon/logo.svgwww.bt.cn/static/astro/icon/logo.sv... https://www.bt.cn/static/astro/icon/logo.svg — 200 — 47.2 KiB — 652 ms — h2https://www.bt.cn/static/astro/js/Header.astro_astro_type_script_index_0_lang.js?version=1776821593www.bt.cn/static/astro/js/Header.as... https://www.bt.cn/static/astro/js/Header.astro_astro_type_script_index_0_lang.js?version=1776821593 — 200 — 558 B — 437 ms — h2https://www.bt.cn/static/astro/images/home/free-icon.pngwww.bt.cn/static/astro/images/home/... https://www.bt.cn/static/astro/images/home/free-icon.png — 200 — 3.2 KiB — 441 ms — h2https://www.bt.cn/static/astro/images/home/banner-1/banner-bg-1.pngwww.bt.cn/static/astro/images/home/... https://www.bt.cn/static/astro/images/home/banner-1/banner-bg-1.png — 200 — 274.3 KiB — 1.3 s — h2https://www.bt.cn/static/astro/images/home/banner-1/bt_video.gifwww.bt.cn/static/astro/images/home/... https://www.bt.cn/static/astro/images/home/banner-1/bt_video.gif — 200 — 2.7 MiB — 2.6 s — h2https://www.bt.cn/static/astro/images/decoration/panel-pc.pngwww.bt.cn/static/astro/images/decor... https://www.bt.cn/static/astro/images/decoration/panel-pc.png — 200 — 12.5 KiB — 858 ms — h2https://www.bt.cn/static/astro/images/home/banner-1/banner-bg-2.pngwww.bt.cn/static/astro/images/home/... https://www.bt.cn/static/astro/images/home/banner-1/banner-bg-2.png — 200 — 228.5 KiB — 1.7 s — h2https://www.bt.cn/static/astro/images/home/banner-1/banner-domain-overview.pngwww.bt.cn/static/astro/images/home/... https://www.bt.cn/static/astro/images/home/banner-1/banner-domain-overview.png — 200 — 167.7 KiB — 1.3 s — h2https://www.bt.cn/static/astro/images/home/banner-1/banner-bg-3.pngwww.bt.cn/static/astro/images/home/... https://www.bt.cn/static/astro/images/home/banner-1/banner-bg-3.png — 200 — 314.7 KiB — 2.6 s — h2https://www.bt.cn/static/astro/images/home/banner-1/banner-ssl-overview.pngwww.bt.cn/static/astro/images/home/... https://www.bt.cn/static/astro/images/home/banner-1/banner-ssl-overview.png — 200 — 97.3 KiB — 1.3 s — h2https://www.bt.cn/static/astro/js/StoryCarousel.astro_astro_type_script_index_0_lang.js?version=1776821593www.bt.cn/static/astro/js/StoryCaro... https://www.bt.cn/static/astro/js/StoryCarousel.astro_astro_type_script_index_0_lang.js?version=1776821593 — 200 — 3.2 KiB — 436 ms — h2https://bat.bing.com/p/action/97128650.jsbat.bing.com/p/action/97128650.js https://bat.bing.com/p/action/97128650.js — 200 — 1.8 KiB — 36 ms — h2https://www.clarity.ms/tag/uet/97128650?insights=1www.clarity.ms/tag/uet/97128650?ins... https://www.clarity.ms/tag/uet/97128650?insights=1 — 200 — 1.0 KiB — 134 ms — http/1.1https://scripts.clarity.ms/0.8.59/clarity.jsscripts.clarity.ms/0.8.59/clarity.j... https://scripts.clarity.ms/0.8.59/clarity.js — 200 — 26.2 KiB — 151 ms — h2https://www.bt.cn/static/astro/js/Layout.astro_astro_type_script_index_0_lang.js?version=1776821593www.bt.cn/static/astro/js/Layout.as... https://www.bt.cn/static/astro/js/Layout.astro_astro_type_script_index_0_lang.js?version=1776821593 — 200 — 5.5 KiB — 650 ms — h2https://www.bt.cn/static/astro/js/utils-vendor.js?version=1776821593www.bt.cn/static/astro/js/utils-ven... https://www.bt.cn/static/astro/js/utils-vendor.js?version=1776821593 — 200 — 60.7 KiB — 666 ms — h2https://www.bt.cn/static/astro/js/vue-vendor.js?version=1776821593www.bt.cn/static/astro/js/vue-vendo... https://www.bt.cn/static/astro/js/vue-vendor.js?version=1776821593 — 200 — 39.0 KiB — 665 ms — h2https://www.bt.cn/static/astro/js/__commonjsHelpers__.js?version=1776821593www.bt.cn/static/astro/js/__commonj... https://www.bt.cn/static/astro/js/__commonjsHelpers__.js?version=1776821593 — 200 — 457 B — 651 ms — h2https://www.bt.cn/static/astro/woff2/fa-solid-900.woff2www.bt.cn/static/astro/woff2/fa-sol... https://www.bt.cn/static/astro/woff2/fa-solid-900.woff2 — 200 — 111.0 KiB — 580 ms — h2https://www.bt.cn/static/astro/images/trust/fuli.pngwww.bt.cn/static/astro/images/trust... https://www.bt.cn/static/astro/images/trust/fuli.png — 200 — 33.2 KiB — 766 ms — h2https://www.bt.cn/static/astro/images/trust/hunan.pngwww.bt.cn/static/astro/images/trust... https://www.bt.cn/static/astro/images/trust/hunan.png — 200 — 30.5 KiB — 768 ms — h2https://www.bt.cn/static/astro/images/trust/njsj.pngwww.bt.cn/static/astro/images/trust... https://www.bt.cn/static/astro/images/trust/njsj.png — 200 — 34.5 KiB — 768 ms — h2https://www.bt.cn/static/astro/images/trust/xiehui.pngwww.bt.cn/static/astro/images/trust... https://www.bt.cn/static/astro/images/trust/xiehui.png — 200 — 62.1 KiB — 773 ms — h2
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s 6.0 s FCP 2.7 s LCP 4.3 shttps://bt.cn// https://bt.cn/ — 302 — 107 B — 700 ms — h2https://www.bt.cn/www.bt.cn/ https://www.bt.cn/ — 302 — 321 B — 694 ms — h2https://www.bt.cn/new/index.htmlwww.bt.cn/new/index.html https://www.bt.cn/new/index.html — 200 — 20.3 KiB — 500 ms — h2https://bat.bing.com/bat.js?version=1776821593bat.bing.com/bat.js?version=1776821... https://bat.bing.com/bat.js?version=1776821593 — 200 — 15.5 KiB — 123 ms — h2https://hm.baidu.com/hm.js?6e78ef648057d9f2ab12dcc287b440f6hm.baidu.com/hm.js?6e78ef648057d9f2... https://hm.baidu.com/hm.js?6e78ef648057d9f2ab12dcc287b440f6 — 200 — 19.6 KiB — 841 ms — http/1.1https://www.bt.cn/static/astro/css/index.css?version=1776821593www.bt.cn/static/astro/css/index.cs... https://www.bt.cn/static/astro/css/index.css?version=1776821593 — 200 — 3.2 KiB — 217 ms — h2https://www.bt.cn/static/astro/css/1111-1.css?version=1776821593www.bt.cn/static/astro/css/1111-1.c... https://www.bt.cn/static/astro/css/1111-1.css?version=1776821593 — 200 — 53.6 KiB — 444 ms — h2https://www.bt.cn/static/astro/icon/logo.svgwww.bt.cn/static/astro/icon/logo.sv... https://www.bt.cn/static/astro/icon/logo.svg — 200 — 47.2 KiB — 652 ms — h2https://www.bt.cn/static/astro/js/Header.astro_astro_type_script_index_0_lang.js?version=1776821593www.bt.cn/static/astro/js/Header.as... https://www.bt.cn/static/astro/js/Header.astro_astro_type_script_index_0_lang.js?version=1776821593 — 200 — 558 B — 437 ms — h2https://www.bt.cn/static/astro/images/home/free-icon.pngwww.bt.cn/static/astro/images/home/... https://www.bt.cn/static/astro/images/home/free-icon.png — 200 — 3.2 KiB — 441 ms — h2https://www.bt.cn/static/astro/images/home/banner-1/banner-bg-1.pngwww.bt.cn/static/astro/images/home/... https://www.bt.cn/static/astro/images/home/banner-1/banner-bg-1.png — 200 — 274.3 KiB — 1.3 s — h2https://www.bt.cn/static/astro/images/home/banner-1/bt_video.gifwww.bt.cn/static/astro/images/home/... https://www.bt.cn/static/astro/images/home/banner-1/bt_video.gif — 200 — 2.7 MiB — 2.6 s — h2https://www.bt.cn/static/astro/images/decoration/panel-pc.pngwww.bt.cn/static/astro/images/decor... https://www.bt.cn/static/astro/images/decoration/panel-pc.png — 200 — 12.5 KiB — 858 ms — h2https://www.bt.cn/static/astro/images/home/banner-1/banner-bg-2.pngwww.bt.cn/static/astro/images/home/... https://www.bt.cn/static/astro/images/home/banner-1/banner-bg-2.png — 200 — 228.5 KiB — 1.7 s — h2https://www.bt.cn/static/astro/images/home/banner-1/banner-domain-overview.pngwww.bt.cn/static/astro/images/home/... https://www.bt.cn/static/astro/images/home/banner-1/banner-domain-overview.png — 200 — 167.7 KiB — 1.3 s — h2https://www.bt.cn/static/astro/images/home/banner-1/banner-bg-3.pngwww.bt.cn/static/astro/images/home/... https://www.bt.cn/static/astro/images/home/banner-1/banner-bg-3.png — 200 — 314.7 KiB — 2.6 s — h2https://www.bt.cn/static/astro/images/home/banner-1/banner-ssl-overview.pngwww.bt.cn/static/astro/images/home/... https://www.bt.cn/static/astro/images/home/banner-1/banner-ssl-overview.png — 200 — 97.3 KiB — 1.3 s — h2https://www.bt.cn/static/astro/js/StoryCarousel.astro_astro_type_script_index_0_lang.js?version=1776821593www.bt.cn/static/astro/js/StoryCaro... https://www.bt.cn/static/astro/js/StoryCarousel.astro_astro_type_script_index_0_lang.js?version=1776821593 — 200 — 3.2 KiB — 436 ms — h2https://bat.bing.com/p/action/97128650.jsbat.bing.com/p/action/97128650.js https://bat.bing.com/p/action/97128650.js — 200 — 1.8 KiB — 36 ms — h2https://www.clarity.ms/tag/uet/97128650?insights=1www.clarity.ms/tag/uet/97128650?ins... https://www.clarity.ms/tag/uet/97128650?insights=1 — 200 — 1.0 KiB — 134 ms — http/1.1https://scripts.clarity.ms/0.8.59/clarity.jsscripts.clarity.ms/0.8.59/clarity.j... https://scripts.clarity.ms/0.8.59/clarity.js — 200 — 26.2 KiB — 151 ms — h2https://www.bt.cn/static/astro/js/Layout.astro_astro_type_script_index_0_lang.js?version=1776821593www.bt.cn/static/astro/js/Layout.as... https://www.bt.cn/static/astro/js/Layout.astro_astro_type_script_index_0_lang.js?version=1776821593 — 200 — 5.5 KiB — 650 ms — h2https://www.bt.cn/static/astro/js/utils-vendor.js?version=1776821593www.bt.cn/static/astro/js/utils-ven... https://www.bt.cn/static/astro/js/utils-vendor.js?version=1776821593 — 200 — 60.7 KiB — 666 ms — h2https://www.bt.cn/static/astro/js/vue-vendor.js?version=1776821593www.bt.cn/static/astro/js/vue-vendo... https://www.bt.cn/static/astro/js/vue-vendor.js?version=1776821593 — 200 — 39.0 KiB — 665 ms — h2https://www.bt.cn/static/astro/js/__commonjsHelpers__.js?version=1776821593www.bt.cn/static/astro/js/__commonj... https://www.bt.cn/static/astro/js/__commonjsHelpers__.js?version=1776821593 — 200 — 457 B — 651 ms — h2https://www.bt.cn/static/astro/woff2/fa-solid-900.woff2www.bt.cn/static/astro/woff2/fa-sol... 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HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100% of JavaScript execution is third-party
First-party Third-party 990ms · 47KB · ¥49/mo
www.bt.cn
Other
Costly
Execution 806ms
Transfer 20 KB
Monthly Cost ¥40/mo
Unattributable
Other
Optional
Execution 111ms
Transfer 0 KB
Monthly Cost ¥5/mo
Microsoft Clarity
Session Replay
Optional
Execution 72ms
Transfer 26 KB
Monthly Cost ¥4/mo

These scripts may cost more than they're worth

  • www.bt.cn adds 806ms and costs ~¥40/month

100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

www.bt.cn takes 806ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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