C — https://www.polytechnique.edu

Site Health

Score: 73 / 100

Based on 8 categories, 0 sections

How is this calculated?

The overall score is a weighted average of individual category scores. Categories with more impact on user experience and security carry more weight.

Performance 25%Security 25%Accessibility 15%SEO 10%Infrastructure 10%Compliance 8%Content 5%Sustainability 2%

Weights reflect general web best practices. Individual needs may differ.

Top Priorities (5)

Content-Security-Policy header is missing

Security › Security Headers

No Content-Security-Policy header found

Security › Content Security Policy

Page weighs 5.2 MB (5.0 MB transferred)

Performance › Page Weight Budget

1 image(s) missing alt attribute

Accessibility › Alt Text Quality

1 image-in-link without alt text

Accessibility › Alt Text Quality

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[![BeaverCheck](https://beavercheck.com/badge?url=https%3A%2F%2Fwww.polytechnique.edu)](https://beavercheck.com/results/89e1e62d-e1aa-0d06-a657-dd46461c7d95)

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Lighthouse Scores

Industry-standard audits powered by Google Lighthouse.

Performance

Accessibility

Best Practices

100

SEO

Core Web Vitals

Key metrics that affect user experience.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

12.96 s

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

19.98 s

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

148 ms

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

0.094

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

12.96 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.

20.37 s

Detailed Report

Audit breakdown by category with detailed findings.

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Request	Cache TTL	Transfer Size
www.polytechnique.edu/themes/project/css/webfonts/fa-light-300.woff2	0.0 ms	455.2 KiB
www.polytechnique.edu/themes/project/css/webfonts/fa-brands-400.woff2	0.0 ms	117.2 KiB
stats-web.polytechnique.fr/piwik.js	0.0 ms	66.8 KiB
/p.css?s=1&k=fbz7slx&ht=tk&f=6768.6769.6770.6771.6772.677...	604800.0 s	172 B

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

URL	Est Savings
www.polytechnique.edu/themes/project/css/webfonts/fa-light-300.woff2	30 ms
www.polytechnique.edu/themes/project/css/webfonts/fa-brands-400.woff2	20 ms
/af/af619f/00000000000000003b9b00c5/27/l?primer=7cdcb44be...	5.0 ms
/af/2011b6/00000000000000003b9b00c1/27/l?primer=7cdcb44be...	5.0 ms

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.

title: Preconnected origins

value: no origins were preconnected

description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.

title: Preconnect candidates

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

URL	Transfer Size	Duration
/css2?family=Barlow:ital,wght@0,100;0,200;0,300;0,400;0,5...	1.4 KiB	837 ms
cdnjs.cloudflare.com/ajax/libs/slick-lightbox/0.2.12/slick-lightbox.css	1.1 KiB	811 ms
/sites/default/files/css/css_YZDzjvh2mqXXcsCbZWA8iisWDIRB...	673.6 KiB	4.5 s
/sites/default/files/js/js_OZmef4KJtRVchQD0OTwkGGzdxF9Xs9...	230.4 KiB	1.0 s
use.typekit.net/fbz7slx.css	1.0 KiB	759 ms
/p.css?s=1&k=fbz7slx&ht=tk&f=6768.6769.6770.6771.6772.677...	172 B	785 ms
/sites/default/files/css/css_JIP2srmI1s3ucHR_-RSxb1B-pvVq...	9.1 KiB	502 ms
cdn.jsdelivr.net/npm/slick-carousel@1.8.1/slick/slick-theme.css	988 B	150 ms
cdn.jsdelivr.net/npm/slick-carousel@1.8.1/slick/slick.css	998 B	752 ms

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

	URL	Resource Size	Est Savings
Le Drahi-X Novation Center `section.innovation > div.flex > div.right > img`	/sites/default/files/styles/innovation/public/nc-project/...	553.9 KiB	535.9 KiB
div.slick-slide > div.element > a > img.img-fluid `div.slick-slide > div.element > a > img.img-fluid`	/sites/default/files/styles/contenu_slider/public/content...	383.3 KiB	373.5 KiB
L'innovation à l'X `section.innovation > div.flex > div.left > img`	/sites/default/files/styles/innovation/public/nc-project/...	370.9 KiB	352.9 KiB
div.slick-slide > div.element > a > img.img-fluid `div.slick-slide > div.element > a > img.img-fluid`	/sites/default/files/styles/contenu_slider/public/content...	253.0 KiB	243.2 KiB
div.node--home > div.wrapperCard > div.frontCard > img.img-fluid `div.node--home > div.wrapperCard > div.frontCard > img.img-fluid`	/sites/default/files/styles/actu_evenement_home/public/co...	234.4 KiB	210.7 KiB
div.slick-slide > div.element > a > img.img-fluid `div.slick-slide > div.element > a > img.img-fluid`	/sites/default/files/styles/contenu_slider/public/content...	165.1 KiB	157.5 KiB
div.node--home > div.wrapperCard > div.frontCard > img.img-fluid `div.node--home > div.wrapperCard > div.frontCard > img.img-fluid`	/sites/default/files/styles/actu_evenement_home/public/co...	73.6 KiB	49.9 KiB
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...	43.0 KiB	35.1 KiB
Découvrir la Fondation `div.container > div.flex > div.right > img`	/sites/default/files/styles/communaute_logo/public/nc-pro...	18.1 KiB	10.7 KiB
Rejoindre l'AX `div.container > div.flex > div.left > img`	/sites/default/files/styles/communaute_logo/public/nc-pro...	17.1 KiB	9.7 KiB

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

TTI

Diagnostics

Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.

Estimated savings: 170 ms 6.3 KiB

URL	Transfer Size	Est Savings
/modules/custom/nc_project/libraries/tarteaucitron/css/ta...	30.7 KiB	6.3 KiB

Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.

Estimated savings: 330 ms 70.0 KiB

URL	Transfer Size	Est Savings
/modules/custom/nc_project/libraries/tarteaucitron/tartea...	260.1 KiB	70.0 KiB

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Estimated savings: 3.5 s 645.2 KiB

URL	Transfer Size	Est Savings
/sites/default/files/css/css_YZDzjvh2mqXXcsCbZWA8iisWDIRB...	672.6 KiB	621.1 KiB
/modules/custom/nc_project/libraries/tarteaucitron/css/ta...	30.3 KiB	24.1 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Estimated savings: 1.7 s 328.4 KiB

URL	Transfer Size	Est Savings
/modules/custom/nc_project/libraries/tarteaucitron/tartea...	260.1 KiB	192.2 KiB
/sites/default/files/js/js_OZmef4KJtRVchQD0OTwkGGzdxF9Xs9...	229.8 KiB	98.8 KiB
stats-web.polytechnique.fr/piwik.js	66.4 KiB	37.4 KiB

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

URL	Transfer Size
/sites/default/files/css/css_YZDzjvh2mqXXcsCbZWA8iisWDIRB...	673.6 KiB
/sites/default/files/styles/innovation/public/nc-project/...	554.9 KiB
www.polytechnique.edu/themes/project/css/webfonts/fa-light-300.woff2	455.2 KiB
/sites/default/files/styles/contenu_slider/public/content...	384.0 KiB
/sites/default/files/styles/innovation/public/nc-project/...	371.6 KiB
/modules/custom/nc_project/libraries/tarteaucitron/tartea...	260.8 KiB
/sites/default/files/styles/contenu_slider/public/content...	253.6 KiB
www.polytechnique.edu/	239.0 KiB
/sites/default/files/styles/actu_evenement_home/public/co...	235.0 KiB
/sites/default/files/js/js_OZmef4KJtRVchQD0OTwkGGzdxF9Xs9...	230.4 KiB

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

	URL
L'innovation à l'X `section.innovation > div.flex > div.left > img`	/sites/default/files/styles/innovation/public/nc-project/...
Le Drahi-X Novation Center `section.innovation > div.flex > div.right > img`	/sites/default/files/styles/innovation/public/nc-project/...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.node--home > div.wrapperCard > div.frontCard > img.img-fluid `div.node--home > div.wrapperCard > div.frontCard > img.img-fluid`	/sites/default/files/styles/actu_evenement_home/public/co...
div.node--home > div.wrapperCard > div.frontCard > img.img-fluid `div.node--home > div.wrapperCard > div.frontCard > img.img-fluid`	/sites/default/files/styles/actu_evenement_home/public/co...
div.node--home > div.wrapperCard > div.frontCard > img.img-fluid `div.node--home > div.wrapperCard > div.frontCard > img.img-fluid`	/sites/default/files/styles/actu_evenement_home/public/co...
Rejoindre l'AX `div.container > div.flex > div.left > img`	/sites/default/files/styles/communaute_logo/public/nc-pro...
Découvrir la Fondation `div.container > div.flex > div.right > img`	/sites/default/files/styles/communaute_logo/public/nc-pro...
École polytechnique, école d'ingénieur `div.bg-primary > div.flex > div > img`	www.polytechnique.edu/sites/default/files/nc-project/footer/logo.png
Recevoir la newsletter `main > div.newsletter > div.title > img`	/sites/default/files/styles/newsletter_home/public/nc-pro...

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Max Potential First Input Delay 130 ms

●Layout shift culprits

●Optimize DOM size

●Forced reflow

●LCP breakdown

●Modern HTTP

●Optimize viewport for mobile

●JavaScript execution time 0.3 s

●Minimizes main-thread work 1.6 s

●Avoid long main-thread tasks 5 long tasks found

●Avoid non-composited animations 37 animated elements found

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 30 ms

●Server Backend Latencies 40 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Avoid multiple page redirects

●Initial server response time was short Root document took 140 ms

●Avoid large layout shifts 1 layout shift found

○INP breakdown

○LCP request discovery

○User Timing marks and measures

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

ARIA

Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid values. Learn more about valid values for ARIA attributes.

Failing Elements
BACHELOR `div.container > ul#formations > li.nav-item > a#0-tab`

Using ARIA attributes in roles where they are prohibited can mean that important information is not communicated to users of assistive technologies. Learn more about prohibited ARIA roles.

Failing Elements
Open search form `div.flex > div.actions-header > div.search-block > i.fal`
Close search form `div.actions-header > div.search-block > div.searchPopup > i.fal`

These are opportunities to improve the usage of ARIA in your application which may enhance the experience for users of assistive technology, like a screen reader.

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Failing Elements
INTERNATIONAL `div.wrapperCard > div.frontCard > div.caption > div.theme`
ENTREPRENEURIAT, ENTREPRISE, INNOVATION `div.wrapperCard > div.frontCard > div.caption > div.theme`
RECHERCHE `div.wrapperCard > div.frontCard > div.caption > div.theme`
École polytechnique, école d'ingénieur • Réalisation Net.Com 2021 `div.container > div.copyright > div.flex > div`
Mentions légales `nav#block--system-menu-block--footer > ul.menu > li.menu-item > a`
Accessibilité numérique `nav#block--system-menu-block--footer > ul.menu > li.menu-item > a`
Politique de protection des données `nav#block--system-menu-block--footer > ul.menu > li.menu-item > a`
Plan du site `nav#block--system-menu-block--footer > ul.menu > li.menu-item > a`
Gestion des cookies `nav#block--system-menu-block--footer > ul.menu > li.menu-item > a`

Low-contrast text is difficult or impossible for many users to read. Link text that is discernible improves the experience for users with low vision. Learn how to make links distinguishable.

Failing Elements
Net.Com `div.copyright > div.flex > div > a`

These are opportunities to improve the legibility of your content.

Names and labels

Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn how to make links accessible.

Failing Elements
section.actualites-evenements > div.container > div.flex > a.rsLink `section.actualites-evenements > div.container > div.flex > a.rsLink`
section.actualites-evenements > div.container > div.flex > a.rsLink `section.actualites-evenements > div.container > div.flex > a.rsLink`
section.actualites-evenements > div.container > div.flex > a.rsLink `section.actualites-evenements > div.container > div.flex > a.rsLink`
section.actualites-evenements > div.container > div.flex > a.rsLink `section.actualites-evenements > div.container > div.flex > a.rsLink`
section.actualites-evenements > div.container > div.flex > a.rsLink `section.actualites-evenements > div.container > div.flex > a.rsLink`

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.

○Interactive controls are keyboard focusable

○Interactive elements indicate their purpose and state

○The page has a logical tab order

○Visual order on the page follows DOM order

○User focus is not accidentally trapped in a region

○The user's focus is directed to new content added to the page

○HTML5 landmark elements are used to improve navigation

○Offscreen content is hidden from assistive technology

○Custom controls have associated labels

○Custom controls have ARIA roles

●`[aria-*]` attributes match their roles

●`[aria-hidden="true"]` is not present on the document `<body>`

●`[role]`s have all required `[aria-*]` attributes

●Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.

●`[role]`s are contained by their required parent element

●`[role]` values are valid

●`[aria-*]` attributes are valid and not misspelled

●Buttons have an accessible name

●Image elements have `[alt]` attributes

●Form elements have associated labels

●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.

●`button`, `link`, and `menuitem` elements have accessible names

●ARIA attributes are used as specified for the element's role

●Elements with `role="dialog"` or `role="alertdialog"` have accessible names.

●`[aria-hidden="true"]` elements do not contain focusable descendents

●Document has a `<title>` element

●`<html>` element has a `[lang]` attribute

●`<html>` element has a valid value for its `[lang]` attribute

●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).

●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements

●No element has a `[tabindex]` value greater than 0

●Touch targets have sufficient size and spacing.

●`[lang]` attributes have a valid value

●Heading elements appear in a sequentially-descending order

●Document has a main landmark.

●Deprecated ARIA roles were not used

●Uses ARIA roles only on compatible elements

●Identical links have the same purpose.

●Elements with visible text labels have matching accessible names.

○`[accesskey]` values are unique

○ARIA input fields have accessible names

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○Elements with the `role=text` attribute do not have focusable descendents.

○ARIA toggle fields have accessible names

○ARIA `tooltip` elements have accessible names

○ARIA `treeitem` elements have accessible names

○The page contains a heading, skip link, or landmark region

○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.

○Definition list items are wrapped in `<dl>` elements

○ARIA IDs are unique

○No form fields have multiple labels

○`<frame>` or `<iframe>` elements have a title

○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.

○Input buttons have discernible text.

○`<input type="image">` elements have `[alt]` text

○The document does not use `<meta http-equiv="refresh">`

○`<object>` elements have alternate text

○Select elements have associated label elements.

○Skip links are focusable.

○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.

○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.

○`<video>` elements contain a `<track>` element with `[kind="captions"]`

○Tables have different content in the summary attribute and `<caption>`.

○All heading elements contain content.

○Image elements do not have `[alt]` attributes that are redundant text.

○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.

○`<td>` elements in a large `<table>` have one or more table headers.

Best Practices

User Experience

Image natural dimensions should be proportional to the display size and the pixel ratio to maximize image clarity. Learn how to provide responsive images.

	URL	Displayed size	Actual size	Expected size
div.node--home > div.wrapperCard > div.frontCard > img.img-fluid `div.node--home > div.wrapperCard > div.frontCard > img.img-fluid`	/sites/default/files/styles/actu_evenement_home/public/co...	382 x 382	400 x 400	573 x 573

●Uses HTTPS

●Avoids deprecated APIs

●Avoids third-party cookies

●Allows users to paste into input fields

●Avoids requesting the geolocation permission on page load

●Avoids requesting the notification permission on page load

●Displays images with correct aspect ratio

●Page has the HTML doctype

●Properly defines charset

●No browser errors logged to the console

●No issues in the `Issues` panel in Chrome Devtools

●Ensure CSP is effective against XSS attacks

●Use a strong HSTS policy

●Ensure proper origin isolation with COOP

●Mitigate DOM-based XSS with Trusted Types

●Detected JavaScript libraries

●Page has valid source maps

○Redirects HTTP traffic to HTTPS

○Mitigate clickjacking with XFO or CSP

100

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

○Structured data is valid

●Page isn’t blocked from indexing

●Document has a `<title>` element

●Document has a meta description

●Page has successful HTTP status code

●Links have descriptive text

●Links are crawlable

●robots.txt is valid

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

●Document has a valid `rel=canonical`

Lighthouse Scores

Industry-standard audits powered by Google Lighthouse. — Desktop

Performance

Accessibility

Best Practices

SEO

Core Web Vitals

Key metrics that affect user experience. — Desktop

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

2.40 s

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

3.66 s

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

0 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.

2.40 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.

3.66 s

Detailed Report

Audit breakdown by category with detailed findings.

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Request	Cache TTL	Transfer Size
www.polytechnique.edu/themes/project/css/webfonts/fa-light-300.woff2	0.0 ms	455.2 KiB
www.polytechnique.edu/themes/project/css/webfonts/fa-brands-400.woff2	0.0 ms	117.2 KiB
stats-web.polytechnique.fr/piwik.js	0.0 ms	66.8 KiB
/p.css?s=1&k=fbz7slx&ht=tk&f=6768.6769.6770.6771.6772.677...	604800.0 s	172 B

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

URL	Est Savings
www.polytechnique.edu/themes/project/css/webfonts/fa-brands-400.woff2	70 ms
www.polytechnique.edu/themes/project/css/webfonts/fa-light-300.woff2	40 ms
/af/af619f/00000000000000003b9b00c5/27/l?primer=7cdcb44be...	5.0 ms
/af/2011b6/00000000000000003b9b00c1/27/l?primer=7cdcb44be...	5.0 ms

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

	URL	Resource Size	Est Savings
Le Drahi-X Novation Center `section.innovation > div.flex > div.right > img`	/sites/default/files/styles/innovation/public/nc-project/...	553.9 KiB	505.7 KiB
L'innovation à l'X `section.innovation > div.flex > div.left > img`	/sites/default/files/styles/innovation/public/nc-project/...	370.9 KiB	322.6 KiB
div#slick-slide01 > div.element > a > img.img-fluid `div#slick-slide01 > div.element > a > img.img-fluid`	/sites/default/files/styles/contenu_slider/public/content...	383.3 KiB	278.2 KiB
div.node--home > div.wrapperCard > div.frontCard > img.img-fluid `div.node--home > div.wrapperCard > div.frontCard > img.img-fluid`	/sites/default/files/styles/actu_evenement_home/public/co...	234.4 KiB	210.1 KiB
div.slick-slide > div.element > a > img.img-fluid `div.slick-slide > div.element > a > img.img-fluid`	/sites/default/files/styles/contenu_slider/public/content...	253.0 KiB	147.9 KiB
main > section.campus > div.background > img.image `main > section.campus > div.background > img.image`	/sites/default/files/styles/campus/public/nc-project/home...	210.7 KiB	90.0 KiB
div#slick-slide02 > div.element > a > img.img-fluid `div#slick-slide02 > div.element > a > img.img-fluid`	/sites/default/files/styles/contenu_slider/public/content...	165.1 KiB	83.5 KiB
div.node--home > div.wrapperCard > div.frontCard > img.img-fluid `div.node--home > div.wrapperCard > div.frontCard > img.img-fluid`	/sites/default/files/styles/actu_evenement_home/public/co...	73.6 KiB	49.3 KiB
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...	56.6 KiB	46.9 KiB
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...	56.2 KiB	46.5 KiB
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...	58.4 KiB	39.9 KiB
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...	46.4 KiB	36.6 KiB
ÉDUCATION BACHELOR CYCLE INGÉNIEUR MASTER DOCTORAT EXECUTIVE MASTER EXECUTIVE E… `body.path-frontpage > div.dialog-off-canvas-main-canvas > main > section.formation`	www.polytechnique.edu/themes/project/img/home/Blason.png	59.5 KiB	35.2 KiB
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...	43.0 KiB	24.6 KiB
Bachelor `div.container > div#formationsContent > div#tab0 > img`	/sites/default/files/styles/lien_home/public/nc-project/h...	41.0 KiB	18.9 KiB
Découvrir la Fondation `div.container > div.flex > div.right > img`	/sites/default/files/styles/communaute_logo/public/nc-pro...	18.1 KiB	10.7 KiB
Rejoindre l'AX `div.container > div.flex > div.left > img`	/sites/default/files/styles/communaute_logo/public/nc-pro...	17.1 KiB	9.7 KiB

Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading

lhId: page-17-IMG

nodeLabel: div#slick-slide00 > div.element > a > img.img-fluid

path: 1,HTML,1,BODY,0,DIV,1,MAIN,2,SECTION,0,DIV,0,DIV,0,DIV,1,DIV,0,DIV,0,A,0,IMG

selector: div#slick-slide00 > div.element > a > img.img-fluid

snippet: <img loading="lazy" src="/sites/default/files/styles/contenu_slider/public/content/actualites/image…" class="img-fluid image-style-contenu-slider" role="presentation">

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

title: Preconnected origins

value: no origins were preconnected

description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.

title: Preconnect candidates

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

URL	Transfer Size	Duration
/css2?family=Barlow:ital,wght@0,100;0,200;0,300;0,400;0,5...	1.4 KiB	297 ms
/sites/default/files/css/css_YZDzjvh2mqXXcsCbZWA8iisWDIRB...	673.6 KiB	888 ms
cdnjs.cloudflare.com/ajax/libs/slick-lightbox/0.2.12/slick-lightbox.css	1.1 KiB	265 ms
/sites/default/files/js/js_OZmef4KJtRVchQD0OTwkGGzdxF9Xs9...	230.4 KiB	167 ms
/p.css?s=1&k=fbz7slx&ht=tk&f=6768.6769.6770.6771.6772.677...	172 B	204 ms
use.typekit.net/fbz7slx.css	1.0 KiB	205 ms
/sites/default/files/css/css_JIP2srmI1s3ucHR_-RSxb1B-pvVq...	9.1 KiB	56 ms
cdn.jsdelivr.net/npm/slick-carousel@1.8.1/slick/slick-theme.css	1.3 KiB
cdn.jsdelivr.net/npm/slick-carousel@1.8.1/slick/slick.css	651 B	201 ms

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

TTI

Diagnostics

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Estimated savings: 610 ms 652.4 KiB

URL	Transfer Size	Est Savings
/sites/default/files/css/css_YZDzjvh2mqXXcsCbZWA8iisWDIRB...	672.6 KiB	627.8 KiB
/modules/custom/nc_project/libraries/tarteaucitron/css/ta...	30.3 KiB	24.6 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Estimated savings: 60 ms 329.1 KiB

URL	Transfer Size	Est Savings
/modules/custom/nc_project/libraries/tarteaucitron/tartea...	260.1 KiB	192.2 KiB
/sites/default/files/js/js_OZmef4KJtRVchQD0OTwkGGzdxF9Xs9...	229.8 KiB	99.5 KiB
stats-web.polytechnique.fr/piwik.js	66.4 KiB	37.4 KiB

Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.

Estimated savings: 0.0 ms 6.3 KiB

URL	Transfer Size	Est Savings
/modules/custom/nc_project/libraries/tarteaucitron/css/ta...	30.7 KiB	6.3 KiB

Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.

Estimated savings: 0.0 ms 70.0 KiB

URL	Transfer Size	Est Savings
/modules/custom/nc_project/libraries/tarteaucitron/tartea...	260.1 KiB	70.0 KiB

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

URL	Transfer Size
/sites/default/files/css/css_YZDzjvh2mqXXcsCbZWA8iisWDIRB...	673.6 KiB
/sites/default/files/styles/innovation/public/nc-project/...	554.9 KiB
www.polytechnique.edu/themes/project/css/webfonts/fa-light-300.woff2	455.2 KiB
/sites/default/files/styles/contenu_slider/public/content...	384.0 KiB
/sites/default/files/styles/innovation/public/nc-project/...	371.6 KiB
/modules/custom/nc_project/libraries/tarteaucitron/tartea...	260.8 KiB
/sites/default/files/styles/contenu_slider/public/content...	253.6 KiB
www.polytechnique.edu/	239.0 KiB
/sites/default/files/styles/actu_evenement_home/public/co...	235.0 KiB
/sites/default/files/js/js_OZmef4KJtRVchQD0OTwkGGzdxF9Xs9...	230.4 KiB

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

	URL
L'innovation à l'X `section.innovation > div.flex > div.left > img`	/sites/default/files/styles/innovation/public/nc-project/...
Le Drahi-X Novation Center `section.innovation > div.flex > div.right > img`	/sites/default/files/styles/innovation/public/nc-project/...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...
div.node--home > div.wrapperCard > div.frontCard > img.img-fluid `div.node--home > div.wrapperCard > div.frontCard > img.img-fluid`	/sites/default/files/styles/actu_evenement_home/public/co...
div.node--home > div.wrapperCard > div.frontCard > img.img-fluid `div.node--home > div.wrapperCard > div.frontCard > img.img-fluid`	/sites/default/files/styles/actu_evenement_home/public/co...
div.node--home > div.wrapperCard > div.frontCard > img.img-fluid `div.node--home > div.wrapperCard > div.frontCard > img.img-fluid`	/sites/default/files/styles/actu_evenement_home/public/co...
Bachelor `div.container > div#formationsContent > div#tab0 > img`	/sites/default/files/styles/lien_home/public/nc-project/h...
Rejoindre l'AX `div.container > div.flex > div.left > img`	/sites/default/files/styles/communaute_logo/public/nc-pro...
Découvrir la Fondation `div.container > div.flex > div.right > img`	/sites/default/files/styles/communaute_logo/public/nc-pro...
École polytechnique, école d'ingénieur `div.bg-primary > div.flex > div > img`	www.polytechnique.edu/sites/default/files/nc-project/footer/logo.png
Recevoir la newsletter `main > div.newsletter > div.title > img`	/sites/default/files/styles/newsletter_home/public/nc-pro...
ul.menu > li.menu-item > a.link-soutiens > img `ul.menu > li.menu-item > a.link-soutiens > img`	www.polytechnique.edu/themes/project/img/header/little_x.png

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Layout shift culprits

●Optimize DOM size

●Forced reflow

●LCP breakdown

●Modern HTTP

●Optimize viewport for mobile

●Max Potential First Input Delay 30 ms

●JavaScript execution time 0.1 s

●Minimizes main-thread work 0.5 s

●Avoid long main-thread tasks 1 long task found

●Avoid non-composited animations 42 animated elements found

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 30 ms

●Server Backend Latencies 40 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Avoid multiple page redirects

●Initial server response time was short Root document took 150 ms

●Avoid large layout shifts 1 layout shift found

○INP breakdown

○User Timing marks and measures

Accessibility

ARIA

Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid values. Learn more about valid values for ARIA attributes.

Failing Elements
BACHELOR `div.container > ul#formations > li.nav-item > a#0-tab`

Using ARIA attributes in roles where they are prohibited can mean that important information is not communicated to users of assistive technologies. Learn more about prohibited ARIA roles.

Failing Elements
Open search form `div.flex > div.actions-header > div.search-block > i.fal`
Close search form `div.actions-header > div.search-block > div.searchPopup > i.fal`

These are opportunities to improve the usage of ARIA in your application which may enhance the experience for users of assistive technology, like a screen reader.

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Failing Elements
Espace étudiant `div.flex > div.actions-header > div.espace-etudiant > a.link-espace-etudiant`
INTERNATIONAL `div.wrapperCard > div.frontCard > div.caption > div.theme`
ENTREPRENEURIAT, ENTREPRISE, INNOVATION `div.wrapperCard > div.frontCard > div.caption > div.theme`
RECHERCHE `div.wrapperCard > div.frontCard > div.caption > div.theme`
École polytechnique, école d'ingénieur • Réalisation Net.Com 2021 `div.container > div.copyright > div.flex > div`
Mentions légales `nav#block--system-menu-block--footer > ul.menu > li.menu-item > a`
Accessibilité numérique `nav#block--system-menu-block--footer > ul.menu > li.menu-item > a`
Politique de protection des données `nav#block--system-menu-block--footer > ul.menu > li.menu-item > a`
Plan du site `nav#block--system-menu-block--footer > ul.menu > li.menu-item > a`
Gestion des cookies `nav#block--system-menu-block--footer > ul.menu > li.menu-item > a`

Low-contrast text is difficult or impossible for many users to read. Link text that is discernible improves the experience for users with low vision. Learn how to make links distinguishable.

Failing Elements
Net.Com `div.copyright > div.flex > div > a`

These are opportunities to improve the legibility of your content.

Names and labels

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Failing Elements
ul.menu > li.menu-item > a.link-soutiens > img `ul.menu > li.menu-item > a.link-soutiens > img`

Failing Elements
section.actualites-evenements > div.container > div.flex > a.rsLink `section.actualites-evenements > div.container > div.flex > a.rsLink`
section.actualites-evenements > div.container > div.flex > a.rsLink `section.actualites-evenements > div.container > div.flex > a.rsLink`
section.actualites-evenements > div.container > div.flex > a.rsLink `section.actualites-evenements > div.container > div.flex > a.rsLink`
section.actualites-evenements > div.container > div.flex > a.rsLink `section.actualites-evenements > div.container > div.flex > a.rsLink`
section.actualites-evenements > div.container > div.flex > a.rsLink `section.actualites-evenements > div.container > div.flex > a.rsLink`

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.

○Interactive controls are keyboard focusable

○Interactive elements indicate their purpose and state

○The page has a logical tab order

○Visual order on the page follows DOM order

○User focus is not accidentally trapped in a region

○The user's focus is directed to new content added to the page

○HTML5 landmark elements are used to improve navigation

○Offscreen content is hidden from assistive technology

○Custom controls have associated labels

○Custom controls have ARIA roles

●`[aria-*]` attributes match their roles

●`[aria-hidden="true"]` is not present on the document `<body>`

●`[role]`s have all required `[aria-*]` attributes

●Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.

●`[role]`s are contained by their required parent element

●`[role]` values are valid

●`[aria-*]` attributes are valid and not misspelled

●Buttons have an accessible name

●Form elements have associated labels

●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.

●`button`, `link`, and `menuitem` elements have accessible names

●ARIA attributes are used as specified for the element's role

●Elements with `role="dialog"` or `role="alertdialog"` have accessible names.

●`[aria-hidden="true"]` elements do not contain focusable descendents

●Document has a `<title>` element

●`<html>` element has a `[lang]` attribute

●`<html>` element has a valid value for its `[lang]` attribute

●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).

●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements

●No element has a `[tabindex]` value greater than 0

●Touch targets have sufficient size and spacing.

●`[lang]` attributes have a valid value

●Heading elements appear in a sequentially-descending order

●Document has a main landmark.

●Deprecated ARIA roles were not used

●Uses ARIA roles only on compatible elements

●Identical links have the same purpose.

●Elements with visible text labels have matching accessible names.

○`[accesskey]` values are unique

○ARIA input fields have accessible names

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○Elements with the `role=text` attribute do not have focusable descendents.

○ARIA toggle fields have accessible names

○ARIA `tooltip` elements have accessible names

○ARIA `treeitem` elements have accessible names

○The page contains a heading, skip link, or landmark region

○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.

○Definition list items are wrapped in `<dl>` elements

○ARIA IDs are unique

○No form fields have multiple labels

○`<frame>` or `<iframe>` elements have a title

○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.

○Input buttons have discernible text.

○`<input type="image">` elements have `[alt]` text

○The document does not use `<meta http-equiv="refresh">`

○`<object>` elements have alternate text

○Select elements have associated label elements.

○Skip links are focusable.

○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.

○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.

○`<video>` elements contain a `<track>` element with `[kind="captions"]`

○Tables have different content in the summary attribute and `<caption>`.

○All heading elements contain content.

○Image elements do not have `[alt]` attributes that are redundant text.

○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.

○`<td>` elements in a large `<table>` have one or more table headers.

Best Practices

User Experience

Image display dimensions should match natural aspect ratio. Learn more about image aspect ratio.

	URL	Aspect Ratio (Displayed)	Aspect Ratio (Actual)
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...	324 x 350 (0.93)	477 x 479 (1.00)
div.slick-slide > div.node--page--recherche > div.img > img.img-fluid `div.slick-slide > div.node--page--recherche > div.img > img.img-fluid`	/sites/default/files/styles/page_home/public/content/page...	324 x 350 (0.93)	477 x 479 (1.00)

●Uses HTTPS

●Avoids deprecated APIs

●Avoids third-party cookies

●Allows users to paste into input fields

●Avoids requesting the geolocation permission on page load

●Avoids requesting the notification permission on page load

●Serves images with appropriate resolution

●Page has the HTML doctype

●Properly defines charset

●No browser errors logged to the console

●No issues in the `Issues` panel in Chrome Devtools

●Ensure CSP is effective against XSS attacks

●Use a strong HSTS policy

●Ensure proper origin isolation with COOP

●Mitigate DOM-based XSS with Trusted Types

●Detected JavaScript libraries

●Page has valid source maps

○Redirects HTTP traffic to HTTPS

○Mitigate clickjacking with XFO or CSP

SEO

Content Best Practices

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Failing Elements
ul.menu > li.menu-item > a.link-soutiens > img `ul.menu > li.menu-item > a.link-soutiens > img`

Format your HTML in a way that enables crawlers to better understand your app’s content.

○Structured data is valid

●Page isn’t blocked from indexing

●Document has a `<title>` element

●Document has a meta description

●Page has successful HTTP status code

●Links have descriptive text

●Links are crawlable

●robots.txt is valid

●Document has a valid `hreflang`

●Document has a valid `rel=canonical`

Browse & Analyze

Learn

Results for https://www.polytechnique.edu

Site Health

Top Priorities (5)

Lighthouse Scores

Core Web Vitals

Detailed Report

Performance

Insights

Diagnostics

Accessibility

ARIA

Contrast

Names and labels

Best Practices

User Experience

SEO

Lighthouse Scores

Core Web Vitals

Detailed Report

Performance

Insights

Diagnostics

Accessibility

ARIA

Contrast

Names and labels

Best Practices

User Experience

SEO

Content Best Practices

Keyboard Shortcuts