Performance
· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
1.49 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
3.18 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
176 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.000
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
3.13 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.
5.62 s
Page Load Progression
928 ms
1.9 s
2.8 s 3.7 s 4.6 s 5.6 s 6.5 s
7.4 sFPage Weight BudgetAction4.6 MB transferred, 234 requestsFIX
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
Source: web.dev
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.
Source: web.dev
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DJS Execution CostAction2911ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.cctv.com/ | 1552ms | 16ms | 4ms | 3rd |
| Unattributable | 579ms | 124ms | 0ms | 3rd |
| https://r.img.cctvpic.com/photoAlbum/templet/common/DEPA1677135475031621/chanjing_index.js | 228ms | 178ms | 3ms | 3rd |
| https://js.player.cntv.cn/creator/liveplayer_controls.js | 148ms | 94ms | 45ms | 3rd |
| https://js.player.cntv.cn/creator/live.worker.js | 101ms | 4ms | 94ms | 3rd |
| https://r.img.cctvpic.com/library/script/jquery-1.7.2.min.js | 67ms | 46ms | 4ms | 3rd |
| https://js.player.cntv.cn/creator/liveplayer.js | 62ms | 50ms | 9ms | 3rd |
| https://js.player.cntv.cn/creator/hlsp2p.js | 58ms | 44ms | 13ms | 3rd |
| https://r.img.cctvpic.com/photoAlbum/templet/common/DEPA1658908558759922/mylogin.js | 58ms | 36ms | 5ms | 3rd |
| https://www.cctv.com/_ws_sbu/sbu_hc.js | 57ms | 45ms | 2ms | 3rd |
DJS BundlesAction39 scripts, 453 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://js.player.cntv.cn/creator/liveplayer_controls.js | 355 KB | 204 KB (58%) | ✓ | 3rd |
| https://js.player.cntv.cn/creator/hlsp2p.js | 118 KB | 82 KB (70%) | ✓ | 3rd |
| https://www.cctv.com/jk-aging/bundle.js?v=v-1.0.9 | 134 KB | 60 KB (59%) | ✓ | 3rd |
| https://js.player.cntv.cn/creator/liveplayer.js | 64 KB | 36 KB (56%) | ✓ | 3rd |
| https://js.data.cctv.com/__aplus_plugin_cctv.js,aplus_plugin_aplus_u.js | 32 KB | 25 KB (82%) | ✓ | 3rd |
| https://r.img.cctvpic.com/photoAlbum/templet/common/DEPA1658908558759922/mylogin.js | 29 KB | 23 KB (87%) | ✗ | 3rd |
| https://r.img.cctvpic.com/photoAlbum/templet/common/DEPA1406601454073701/jsencrypt.js | 41 KB | 23 KB (57%) | ✗ | 3rd |
| https://www.cctv.com/jk-aging/lib/jquery.cookie.js | 2 KB | — | ✓ | 3rd |
| https://js.player.cntv.cn/creator/html5player_analysis_lib.js | 37 KB | — | ✓ | 3rd |
| https://r.img.cctvpic.com/photoAlbum/templet/common/DEPA1406601454073701/md5login.js | 7 KB | — | ✓ | 3rd |
Consider code splitting or tree shaking to reduce unused code.
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.
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.
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.
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.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
FPage Weight InventoryAction234 resources · 4.6 MB · 453 KB savings availableFIX
~453.5 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 234 resources | 4.6 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction179 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
A+Text CompressionAll text resources are compressedPASS
A+Font LoadingNo web fonts (system fonts)PASS
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall234 requests over 7371msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.cctv.com www.cctv.com | Other | 1552ms | 314 KB | — | ¥77/mo | Costly |
Unattributable Unattributable | Other | 579ms | 0 KB | — | ¥29/mo | Costly |
r.img.cctvpic.com r.img.cctvpic.com | Other | 228ms | 22 KB | — | ¥11/mo | Costly |
js.player.cntv.cn js.player.cntv.cn | Other | 148ms | 355 KB | 58% | ¥7/mo | Optional |
js.player.cntv.cn js.player.cntv.cn | Other | 101ms | 559 KB | — | ¥5/mo | Optional |
r.img.cctvpic.com r.img.cctvpic.com | Other | 67ms | 38 KB | — | ¥3/mo | Optional |
js.player.cntv.cn js.player.cntv.cn | Other | 62ms | 64 KB | 56% | ¥3/mo | Optional |
js.player.cntv.cn js.player.cntv.cn | Other | 58ms | 118 KB | 70% | ¥3/mo | Optional |
r.img.cctvpic.com r.img.cctvpic.com | Other | 58ms | 29 KB | 87% | ¥3/mo | Optional |
www.cctv.com www.cctv.com | Other | 57ms | 32 KB | — | ¥3/mo | Optional |
These scripts may cost more than they're worth
- www.cctv.com adds 1552ms and costs ~¥77/month
- Unattributable adds 579ms and costs ~¥29/month
- r.img.cctvpic.com adds 228ms and costs ~¥11/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
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.cctv.com takes 1552ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Unattributable takes 579ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
r.img.cctvpic.com takes 228ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
58% of js.player.cntv.cn's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
56% of js.player.cntv.cn's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
70% of js.player.cntv.cn's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
87% of r.img.cctvpic.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev