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.
1.40 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.27 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
331 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.049
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
3.57 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.
5.68 s
Page Load Progression
FPage Weight BudgetAction23.6 MB transferred, 126 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 CostAction2265ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.tv-asahi.co.jp/Top24/assets/index.js | 749ms | 226ms | 1ms | 3rd |
| Unattributable | 397ms | 8ms | 0ms | 3rd |
| https://www.tv-asahi.co.jp/ | 324ms | 3ms | 1ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-P3HJF2 | 271ms | 232ms | 30ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-DK0DVKPCR6&cx=c>m=4e64k0h1 | 141ms | 112ms | 27ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-DJWW7JPFSS&cx=c>m=4e64k0h1 | 109ms | 87ms | 21ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-GFX8N57Z5R&cx=c>m=4e64k0h1 | 97ms | 77ms | 19ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-1MF0KVKVN1&cx=c>m=4e64k0h1 | 91ms | 70ms | 20ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-EWDQYCBMEL&cx=c>m=4e64k0h1 | 86ms | 71ms | 14ms | 3rd |
DJS BundlesAction17 scripts, 458 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=G-DJWW7JPFSS&cx=c>m=4e64k0h1 | 169 KB | 71 KB (42%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-DK0DVKPCR6&cx=c>m=4e64k0h1 | 176 KB | 70 KB (40%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-GFX8N57Z5R&cx=c>m=4e64k0h1 | 151 KB | 67 KB (44%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-1MF0KVKVN1&cx=c>m=4e64k0h1 | 143 KB | 65 KB (46%) | ✓ | 3rd |
| https://www.tv-asahi.co.jp/Top24/assets/index.js | 205 KB | 65 KB (32%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-EWDQYCBMEL&cx=c>m=4e64k0h1 | 144 KB | 64 KB (45%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-P3HJF2 | 197 KB | 56 KB (29%) | ✓ | 3rd |
| https://www.tv-asahi.co.jp/mps/bigdata/luid/get_luid.js | 2 KB | — | ✓ | 3rd |
| https://www.tv-asahi.co.jp/mps/bigdata/luid/optout_migration.js | 0 KB | — | ✓ | 3rd |
| https://www.tv-asahi.co.jp/mps/bigdata/luid/opt_init.js | 1 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 InventoryAction126 resources · 23.6 MB · 458 KB savings availableFIX
~458.0 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 126 resources | 23.6 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction78 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
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 Waterfall126 requests over 6595msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.tv-asahi.co.jp www.tv-asahi.co.jp | Other | 749ms | 205 KB | 32% | ¥1035/mo | Costly |
Unattributable Unattributable | Other | 397ms | 0 KB | — | ¥549/mo | Costly |
www.tv-asahi.co.jp www.tv-asahi.co.jp | Other | 324ms | 4 KB | — | ¥448/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 271ms | 197 KB | 29% | ¥374/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 141ms | 176 KB | 40% | ¥195/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 109ms | 169 KB | 42% | ¥151/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 97ms | 151 KB | 44% | ¥133/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 91ms | 143 KB | 46% | ¥126/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 86ms | 144 KB | 45% | ¥119/mo | Costly |
These scripts may cost more than they're worth
- www.tv-asahi.co.jp adds 749ms and costs ~¥1035/month
- Unattributable adds 397ms and costs ~¥549/month
- www.tv-asahi.co.jp adds 324ms and costs ~¥448/month
- Google Tag Manager adds 271ms and costs ~¥374/month
- Google Tag Manager adds 141ms and costs ~¥195/month
- Google Tag Manager adds 109ms and costs ~¥151/month
- Google Tag Manager adds 97ms and costs ~¥133/month
- Google Tag Manager adds 91ms and costs ~¥126/month
- Google Tag Manager adds 86ms and costs ~¥119/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.tv-asahi.co.jp takes 749ms 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 397ms 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
www.tv-asahi.co.jp takes 324ms 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
Google Tag Manager takes 271ms 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
Google Tag Manager takes 141ms 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
Google Tag Manager takes 109ms 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
Google Tag Manager takes 97ms 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
Google Tag Manager takes 91ms 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
Google Tag Manager takes 86ms 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