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https://www.sciencedirect.com

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
91
GRADE
A
FIX
1
REVIEW
4
PASS
7
INFO
2

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

Mobile Desktop
98
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
95
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
92
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
82
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.

759 ms

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

964 ms

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

22 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.007

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

759 ms

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

1.09 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
14
7 PASS 4 REVIEW 1 FIX
D
HTTP Caching
Action
no-store (uncacheable)
FIX
no-store (uncacheable)
Info::
Cache-Control: no-store prevents all caching
Intentional for dynamic content, but increases server load for every page view.
Got: private, max-age=0, no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

private, max-age=0, no-store, no-cache, must-revalidate, post-check=0, pre-check=0

DirectiveValueMeaning
private—Only browser cache, not CDN/proxy
max-age0Cache for 0 seconds
no-store—Never cache this response
no-cache—Cache but always revalidate first
must-revalidate—Must recheck with server after expiry
post-check0
pre-check0
B
Page Weight Budget
1.1 MB transferred, 28 requests
REVIEW
1.1 MB transferred, 28 requests
Info::
Page weighs 1.8 MB (1.1 MB transferred)
Info::
28 HTTP requests
Info::
Estimated 0.22 g CO2 per page load
1.1 MB / 2.4 MB budget
1.1 MB transferred
28 requests
0.22 g CO2 per page load
HTML 611.0 KiB 56%
Other 294.1 KiB 27%
JavaScript 85.6 KiB 8%
Fonts 67.7 KiB 6%
Images 30.4 KiB 3%
Other 1.7 KiB 0%
Other 74 B 0%
Other 71 B 0%
0 2.4 MB 4.9 MB
Under budget
B
Third-Party Impact
45% third-party, 0 ms blocking
REVIEW
45% third-party, 0 ms blocking
Info::
Third-party code accounts for 45% of page weight (490.7 KiB of 1.1 MiB)
Info::
Third-party blocking time is low (0 ms)
55%
45%
First-party Third-party
B
Image Optimization
6 images, 0 KB saveable
REVIEW
6 images, 0 KB saveable
Info::
All images are well-optimized
6 images 30 KB
0 oversized -0 KB
4 legacy format
0 missing dimensions CLS risk
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+
JS Execution Cost
409ms total JS execution
PASS
409ms total JS execution
Warning::
https://www.sciencedirect.com/cdn-cgi/challenge-pl...: 281ms CPU time
Info::
Unattributable: 74ms CPU time
Info::
https://www.sciencedirect.com/: 54ms CPU time
Info::
Third-party scripts: 74ms (18% of total)

Main Thread Breakdown

Script Evaluation 68% Other 18% Style & Layout 6% Parse HTML & CSS 3%
ScriptTotalScriptingParse/CompileParty
https://www.sciencedirect.com/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9e8ba46219930345281ms268ms4ms1st
Unattributable74ms2ms0ms3rd
https://www.sciencedirect.com/54ms7ms1ms1st
A+
Font Loading
2 fonts (68 KB)
PASS
2 fonts (68 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

68 KB total

Render-blocking

0

of 2

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s FCP 759 ms LCP 964 msdata:binary/octet-stream;base64,d09GMgABAAAAAIegABEAAAABpYAAAIc7AAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGjo…octet-stream;base64,d09... data:binary/octet-stream;base64,d09GMgABAAAAAIegABEAAAABpYAAAIc7AAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGjo… — 33.9 KiB — 0 ms — font-display: swapdata:binary/octet-stream;base64,d09GMgABAAAAAIdEABEAAAABpRgAAIbiAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGjo…octet-stream;base64,d09... data:binary/octet-stream;base64,d09GMgABAAAAAIdEABEAAAABpRgAAIbiAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGjo… — 33.8 KiB — 0 ms — font-display: swap
octet-stream;base64,d09... unknown swap
Size 34 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
octet-stream;base64,d09... unknown swap
Size 34 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
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 ~20 KB and ~40 ms

A+
JS Bundles
11 scripts, 0 KB unused
PASS
11 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.sciencedirect.com/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9e8ba4621993034568 KB—✓1st
blob:https://www.sciencedirect.com/7e2b9139-f5d3-4c90-a45b-04ff39ed80070 KB—✓3rd
https://challenges.cloudflare.com/turnstile/v0/b/625261456364/api.js?onload=OBvX9&render=explicit17 KB—✓3rd
blob:https://www.sciencedirect.com/0b015b8b-3694-4368-8e7f-d6e602f45ab1-0 KB—✓3rd
blob:https://challenges.cloudflare.com/ec0a9438-86cf-4869-85d1-41b8d12fdc520 KB—✓3rd
blob:https://challenges.cloudflare.com/3d2a2957-658f-4832-97d6-927feed8f509-0 KB—✓3rd
blob:https://challenges.cloudflare.com/3d2a2957-658f-4832-97d6-927feed8f509-0 KB—✓3rd
blob:https://challenges.cloudflare.com/3d2a2957-658f-4832-97d6-927feed8f509-0 KB—✓3rd
blob:https://challenges.cloudflare.com/3d2a2957-658f-4832-97d6-927feed8f509-0 KB—✓3rd
blob:https://challenges.cloudflare.com/3d2a2957-658f-4832-97d6-927feed8f509-0 KB—✓3rd
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
28 requests over 0ms
INFO

Performance analysis not available for this result.

Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
18% of JavaScript execution is third-party
First-party Third-party 74ms · 0KB · $1/mo
Unattributable
Other
Optional
Execution 74ms
Transfer 0 KB
Monthly Cost $1/mo

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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