Performance
· 17 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.
7.04 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
10.14 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
2.34 s
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.259
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
16.17 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.
17.86 s
Page Load Progression
1.9 s 3.8 s
5.7 s
7.6 s
9.5 s
11.4 s 13.3 s
15.2 sFPage Weight BudgetAction12.4 MB transferred, 219 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
FJS Execution CostAction15525ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://m.dangdang.com/static/js/pages-index-index.d1ec2626.js | 6346ms | 4472ms | 67ms | 3rd |
| https://m.dangdang.com/ | 3010ms | 72ms | 2ms | 3rd |
| https://m.dangdang.com/static/js/chunk-vendors.27c32229.js | 2235ms | 706ms | 95ms | 3rd |
| Unattributable | 1579ms | 11ms | 0ms | 3rd |
| https://static.dangdang.com/fed/accessbility-wap/1.0.0/accessbility.min.js | 1285ms | 1026ms | 138ms | 3rd |
| https://m.dangdang.com/static/js/index.584f11bc.js | 645ms | 576ms | 19ms | 3rd |
| https://databack.dangdang.com/collect.js?20190402 | 424ms | 403ms | 5ms | 3rd |
DJS BundlesAction18 scripts, 169 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://m.dangdang.com/static/js/chunk-vendors.27c32229.js | 224 KB | 113 KB (51%) | ✓ | 3rd |
| https://static.dangdang.com/fed/accessbility-wap/1.0.0/accessbility.min.js | 123 KB | 33 KB (27%) | ✗ | 3rd |
| https://m.dangdang.com/static/js/pages-index-index.d1ec2626.js | 75 KB | 23 KB (32%) | ✓ | 3rd |
| https://m.dangdang.com/static/js/pages-ddReading-bookListSquare-bookListSquareDetail~pages-ddReading-bookshelf-booklist~pages-ddReadi~eb1bef47.749e6517.js | 5 KB | — | ✓ | 3rd |
| https://static.dangdang.com/fed/js-bridge/2.0.0/bridge.min.js | 1 KB | — | ✓ | 3rd |
| https://databack.dangdang.com/collect.js?20190402 | 12 KB | — | ✓ | 3rd |
| https://m.dangdang.com/static/js/pages-bookmark-bookmarkNew~pages-bookmark-detail~pages-bookmark-yearlyReport~pages-certification-liv~c2882473.36d11324.js | 7 KB | — | ✓ | 3rd |
| https://m.dangdang.com/static/js/pages-coupon-awardCoupon~pages-coupon-communityCoupon~pages-coupon-purchaseCoupon~pages-index-index~~b5dcea02.8b41b960.js | 12 KB | — | ✓ | 3rd |
| https://m.dangdang.com/static/js/index.584f11bc.js | 32 KB | — | ✓ | 3rd |
| https://m.dangdang.com/static/js/pages-ddReading-bookshelf-booklist~pages-ddReading-bookshelf-bookmark~pages-ddReading-bookshelf-book~faf50d6d.12fe226f.js | 8 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
DPage Weight InventoryAction219 resources · 12.4 MB · 169 KB savings availableFIX
~168.5 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 219 resources | 12.4 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BImage Optimization169 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
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 Loading1 fonts (36 KB)PASS
Web fonts
1
36 KB total
Render-blocking
0
of 1
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Convert to woff2 for ~30% smaller file size
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 ~11 KB and ~22 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
Network Waterfall219 requests over 15317msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
m.dangdang.com m.dangdang.com | Other | 6346ms | 75 KB | 32% | ¥259/mo | Costly |
m.dangdang.com m.dangdang.com | Other | 3010ms | 2 KB | — | ¥123/mo | Costly |
m.dangdang.com m.dangdang.com | Other | 2235ms | 224 KB | 51% | ¥91/mo | Costly |
Unattributable Unattributable | Other | 1579ms | 0 KB | — | ¥65/mo | Costly |
static.dangdang.com static.dangdang.com | Other | 1285ms | 123 KB | 27% | ¥53/mo | Costly |
m.dangdang.com m.dangdang.com | Other | 645ms | 32 KB | — | ¥26/mo | Costly |
databack.dangdang.com databack.dangdang.com | Other | 424ms | 12 KB | — | ¥17/mo | Costly |
These scripts may cost more than they're worth
- m.dangdang.com adds 6346ms and costs ~¥259/month
- m.dangdang.com adds 3010ms and costs ~¥123/month
- m.dangdang.com adds 2235ms and costs ~¥91/month
- Unattributable adds 1579ms and costs ~¥65/month
- static.dangdang.com adds 1285ms and costs ~¥53/month
- m.dangdang.com adds 645ms and costs ~¥26/month
- databack.dangdang.com adds 424ms and costs ~¥17/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
m.dangdang.com takes 6346ms 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
m.dangdang.com takes 3010ms 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
m.dangdang.com takes 2235ms 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
51% of m.dangdang.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
Unattributable takes 1579ms 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
static.dangdang.com takes 1285ms 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
m.dangdang.com takes 645ms 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
databack.dangdang.com takes 424ms 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