Report Summary

  • 7

    Performance

    Renders faster than
    30% of other websites

  • 94

    Accessibility

    Visual factors better than
    that of 88% of websites

  • 92

    Best Practices

    More advanced features
    available than in
    86% of websites

  • 93

    SEO

    Google-friendlier than
    88% of websites

cern.ch

Home | CERN

Page Load Speed

3.2 sec in total

First Response

275 ms

Resources Loaded

2.8 sec

Page Rendered

150 ms

cern.ch screenshot

About Website

Welcome to cern.ch homepage info - get ready to check CERN best content for China right away, or after learning these important things about cern.ch

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Univer...

Visit cern.ch

Key Findings

We analyzed Cern.ch page load time and found that the first response time was 275 ms and then it took 2.9 sec to load all DOM resources and completely render a web page. This is quite a good result, as only 45% of websites can load faster.

Performance Metrics

cern.ch performance score

7

Measured Metrics

name

value

score

weighting

FCP (First Contentful Paint)

Value4.6 s

14/100

10%

LCP (Largest Contentful Paint)

Value28.4 s

0/100

25%

SI (Speed Index)

Value11.9 s

4/100

10%

TBT (Total Blocking Time)

Value1,510 ms

14/100

30%

CLS (Cumulative Layout Shift)

Value0.692

7/100

15%

TTI (Time to Interactive)

Value18.3 s

3/100

10%

Network Requests Diagram

cern.ch

275 ms

home.cern

375 ms

css_ywqYrtSodM0qVMzAkOSnqZ_iBnAVpkSeD_yPtUN9tBk.css

92 ms

css_PIoIEC4HnZPBCk5XKIsbeV6CMSyX66A5f4ymmZ7DCUA.css

182 ms

css_jF0Zbf-OleWOug30HRVzE2aiN5qhdf1wXZteyandyzc.css

182 ms

Our browser made a total of 27 requests to load all elements on the main page. We found that 4% of them (1 request) were addressed to the original Cern.ch, 63% (17 requests) were made to Home.cern and 26% (7 requests) were made to Framework.web.cern.ch. The less responsive or slowest element that took the longest time to load (813 ms) relates to the external source Framework.web.cern.ch.

Page Optimization Overview & Recommendations

Page size can be reduced by 383.1 kB (65%)

Content Size

586.9 kB

After Optimization

203.7 kB

In fact, the total size of Cern.ch main page is 586.9 kB. This result falls beyond the top 1M of websites and identifies a large and not optimized web page that may take ages to load. 25% of websites need less resources to load. Javascripts take 266.8 kB which makes up the majority of the site volume.

HTML Optimization

-70%

Potential reduce by 15.1 kB

  • Original 21.6 kB
  • After minification 20.2 kB
  • After compression 6.4 kB

HTML content can be minified and compressed by a website’s server. The most efficient way is to compress content using GZIP which reduces data amount travelling through the network between server and browser. HTML code on this page is well minified. It is highly recommended that content of this web page should be compressed using GZIP, as it can save up to 15.1 kB or 70% of the original size.

Image Optimization

-8%

Potential reduce by 7.3 kB

  • Original 90.7 kB
  • After minification 83.3 kB

Image size optimization can help to speed up a website loading time. The chart above shows the difference between the size before and after optimization. CERN images are well optimized though.

JavaScript Optimization

-71%

Potential reduce by 189.4 kB

  • Original 266.8 kB
  • After minification 209.4 kB
  • After compression 77.4 kB

It’s better to minify JavaScript in order to improve website performance. The diagram shows the current total size of all JavaScript files against the prospective JavaScript size after its minification and compression. It is highly recommended that all JavaScript files should be compressed and minified as it can save up to 189.4 kB or 71% of the original size.

CSS Optimization

-82%

Potential reduce by 171.3 kB

  • Original 207.9 kB
  • After minification 201.9 kB
  • After compression 36.6 kB

CSS files minification is very important to reduce a web page rendering time. The faster CSS files can load, the earlier a page can be rendered. Cern.ch needs all CSS files to be minified and compressed as it can save up to 171.3 kB or 82% of the original size.

Requests Breakdown

Number of requests can be reduced by 12 (63%)

Requests Now

19

After Optimization

7

The browser has sent 19 CSS, Javascripts, AJAX and image requests in order to completely render the main page of CERN. We recommend that multiple CSS and JavaScript files should be merged into one by each type, as it can help reduce assets requests from 7 to 1 for JavaScripts and from 7 to 1 for CSS and as a result speed up the page load time.

Accessibility Review

cern.ch accessibility score

94

Accessibility Issues

Contrast

These are opportunities to improve the legibility of your content.

Impact

Issue

High

Background and foreground colors do not have a sufficient contrast ratio.

Navigation

These are opportunities to improve keyboard navigation in your application.

Impact

Issue

High

Heading elements are not in a sequentially-descending order

Names and labels

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Impact

Issue

High

Links do not have a discernible name

Best Practices

cern.ch best practices score

92

Areas of Improvement

Trust and Safety

Impact

Issue

High

Does not use HTTPS

Low

Ensure CSP is effective against XSS attacks

General

Impact

Issue

Low

Detected JavaScript libraries

SEO Factors

cern.ch SEO score

93

Search Engine Optimization Advices

Crawling and Indexing

To appear in search results, crawlers need access to your app.

Impact

Issue

High

Links are not crawlable

Mobile Friendly

Make sure your pages are mobile friendly so users don’t have to pinch or zoom in order to read the content pages. [Learn more](https://developers.google.com/search/mobile-sites/).

Impact

Issue

High

Document uses legible font sizes

Language and Encoding

  • Language Detected

    EN

  • Language Claimed

    EN

  • Encoding

    UTF-8

Language claimed in HTML meta tag should match the language actually used on the web page. Otherwise Cern.ch can be misinterpreted by Google and other search engines. Our service has detected that English is used on the page, and it matches the claimed language. Our system also found out that Cern.ch main page’s claimed encoding is utf-8. Use of this encoding format is the best practice as the main page visitors from all over the world won’t have any issues with symbol transcription.

Social Sharing Optimization

Open Graph description is not detected on the main page of CERN. Lack of Open Graph description can be counter-productive for their social media presence, as such a description allows converting a website homepage (or other pages) into good-looking, rich and well-structured posts, when it is being shared on Facebook and other social media. For example, adding the following code snippet into HTML <head> tag will help to represent this web page correctly in social networks: