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.
2.56 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
3.91 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
34 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.001
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
4.29 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.
4.06 s
Page Load Progression
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction92 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
BJS Execution Cost910ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.ctrip.com/ | 410ms | 10ms | 2ms | 3rd |
| Unattributable | 221ms | 53ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-B77BES1Z8Z&cx=c>m=4e64k0h2 | 103ms | 84ms | 16ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-9BZF483VNQ&cx=c>m=4e64k0h2 | 63ms | 51ms | 11ms | 3rd |
| https://ak-s-cw.tripcdn.com/NFES/mfe_compose/1776259394825/compose.js | 60ms | 48ms | 9ms | 3rd |
| https://ak-s-cw.tripcdn.com/modules/ubt/websdk/ubt.minl.1b556081277eed0f1aed5e7bda2f4f9c.js | 54ms | 48ms | 4ms | 3rd |
CJS BundlesAction39 scripts, 224 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=G-9BZF483VNQ&cx=c>m=4e64k0h2 | 158 KB | 66 KB (42%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-B77BES1Z8Z&cx=c>m=4e64k0h2 | 178 KB | 64 KB (36%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-NS9686L5 | 117 KB | 63 KB (54%) | ✓ | 3rd |
| https://static.tripcdn.com/packages/market/mktadsdk/%5E1.0.0/common/js/adsdkswiper.min.js | 34 KB | 31 KB (89%) | ✓ | 3rd |
| https://static.tripcdn.com/packages/market/mkt-union-tracing/*/ResUnionOnline/float/pcfloat.min.js | 1 KB | — | ✓ | 3rd |
| https://webresource.c-ctrip.com/ares2/train/csec/*/default/sec/c-sec.js?v=2026421 | 0 KB | — | ✓ | 3rd |
| https://webresource.c-ctrip.com/NFES/mfe_travelMap/1761035706085/travelMap.js | 0 KB | — | ✓ | 3rd |
| https://ak-s-cw.tripcdn.com/NFES/mfe_platformAdvertStairs/1768217817972/platformAdvertStairs.js | 0 KB | — | ✓ | 3rd |
| https://ak-s-cw.tripcdn.com/NFES/mfe_marketPlayer/1742882593896/marketPlayer.js | 0 KB | — | ✓ | 3rd |
| https://ak-s-cw.tripcdn.com/NFES/mfe_platformSeoFoot/1749709256172/platformSeoFoot.js | 0 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
BPage Weight Inventory182 resources · 649 KB · 224 KB savings availableREVIEW
~223.7 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 182 resources | 649.0 KiB | ||||||
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
A+Page Weight Budget649 KB transferred, 182 requestsPASS
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
A+Text CompressionAll text resources are compressedPASS
A+Font Loading1 fonts (0 KB)PASS
Web fonts
1
0 KB total
Render-blocking
0
of 1
Dominant font-display
swap
Most common across fonts
Font loading timeline
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)
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall182 requests over 8419msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.ctrip.com www.ctrip.com | Other | 410ms | 62 KB | — | ¥20/mo | Costly |
Unattributable Unattributable | Other | 221ms | 0 KB | — | ¥11/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 103ms | 178 KB | 36% | ¥5/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 63ms | 158 KB | 42% | ¥3/mo | Optional |
ak-s-cw.tripcdn.com ak-s-cw.tripcdn.com | Other | 60ms | 0 KB | — | ¥3/mo | Optional |
ak-s-cw.tripcdn.com ak-s-cw.tripcdn.com | Other | 54ms | 0 KB | — | ¥3/mo | Optional |
These scripts may cost more than they're worth
- www.ctrip.com adds 410ms and costs ~¥20/month
- Unattributable adds 221ms 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.ctrip.com takes 410ms 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 221ms 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