Lighthouse Mobile

· 0 checks — Mobile Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Request	Cache TTL	Transfer Size
/wp-content/uploads/2022/12/EPFL-vue-aerienne-Jamani-Cail...	0.0 ms	348.3 KiB
actu.epfl.ch/image/163596/1440x810.jpg	0.0 ms	312.2 KiB
www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1	0.0 ms	84.5 KiB
/wp-content/themes/wp-theme-2018/assets/js/vendors.min.js...	0.0 ms	80.3 KiB
www.epfl.ch/wp-content/uploads/2026/04/Anna-Fontcuberta-i-Morral-768x432.jpg	0.0 ms	58.9 KiB
/wp-content/themes/wp-theme-2018/assets/css/elements.min....	0.0 ms	52.3 KiB
www.epfl.ch/wp-content/uploads/2026/03/dimensions-num20-flipbook-768x432.jpg	0.0 ms	50.8 KiB
www.epfl.ch/wp-content/uploads/2026/04/David-Atienza-768x432.jpg	0.0 ms	38.7 KiB
memento.epfl.ch/image/32970/509x286.jpg	900.0 s	38.7 KiB
memento.epfl.ch/image/32754/509x286.jpg	900.0 s	36.3 KiB
memento.epfl.ch/image/32144/509x286.jpg	900.0 s	31.4 KiB
memento.epfl.ch/image/32730/509x286.jpg	900.0 s	31.1 KiB
memento.epfl.ch/image/32071/509x286.jpg	900.0 s	28.8 KiB
/wp-content/themes/wp-theme-2018/assets/js/elements.min.j...	0.0 ms	21.3 KiB
www.epfl.ch/fonts/SuisseIntl-SemiBold-WebS.woff2	0.0 ms	18.3 KiB
www.epfl.ch/fonts/SuisseIntl-Regular-WebS.woff2	0.0 ms	17.9 KiB
www.epfl.ch/wp-includes/js/jquery/jquery-migrate.js?ver=3.4.1	0.0 ms	11.3 KiB
/wp-content/plugins/enlighter/cache/enlighterjs.min.css?v...	0.0 ms	10.2 KiB
www.epfl.ch/wp-includes/js/twemoji.js?ver=6.9.4	0.0 ms	9.8 KiB
/wp-content/themes/wp-theme-2018/assets/css/vendors.min.c...	0.0 ms	7.7 KiB
/wp-content/plugins/wp-gutenberg-epfl/frontend/lib/list.m...	0.0 ms	7.2 KiB
www.epfl.ch/wp-content/uploads/2021/09/Recherche.png	0.0 ms	6.0 KiB
www.epfl.ch/wp-content/uploads/2021/09/Facultes.png	0.0 ms	4.7 KiB
www.epfl.ch/wp-content/uploads/2021/09/Education.png	0.0 ms	4.7 KiB
www.epfl.ch/wp-content/uploads/2021/09/Innovation.png	0.0 ms	4.6 KiB
www.epfl.ch/wp-includes/js/wp-emoji.js?ver=6.9.4	0.0 ms	4.4 KiB
/wp-content/plugins/flowpaper-lite-pdf-flipbook/assets/li...	0.0 ms	3.9 KiB
www.epfl.ch/wp-content/uploads/2021/09/Campus.png	0.0 ms	3.8 KiB
/wp-content/plugins/wp-gutenberg-epfl/build/style-index.c...	0.0 ms	2.1 KiB
www.epfl.ch/wp-content/themes/wp-theme-2018/theme/style.min.css?ver=1776380526	0.0 ms	2.0 KiB
www.epfl.ch/wp-content/uploads/2025/03/EPFL-logo.png	0.0 ms	1.9 KiB
www.epfl.ch/wp-content/themes/wp-theme-2018/assets/svg/epfl-logo.svg	0.0 ms	1.6 KiB
www.epfl.ch/wp-content/themes/wp-theme-2018/style.css?ver=1776380526	0.0 ms	1.4 KiB

Layout shifts occur when elements move absent any user interaction. Investigate the causes of layout shifts, such as elements being added, removed, or their fonts changing as the page loads.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:node label:Element subItemsHeading:map[key:extra] valueType:node] map[granularity:0.001 key:score label:Layout shift score subItemsHeading:map[key:cause valueType:text] valueType:numeric]]

items: [map[node:map[type:text value:Total] score:0.145757] map[node:map[boundingRect:map[bottom:866 height:312 left:0 right:412 top:554 width:412] lhId:page-10-DIV nodeLabel:Lighting up the organizers of the cell's architecture NewsResearch Scientists … path:1,HTML,1,BODY,1,DIV,7,DIV,0,DIV,2,DIV,0,MAIN,0,ARTICLE,0,DIV,3,DIV,0,DIV,0,DIV,1,DIV selector:div.container-full > div.list-group > div.fullwidth-teaser > div.fullwidth-teaser-text snippet:<div class="fullwidth-teaser-text"> type:node] score:0.145757 subItems:map[items:[map[cause:Unsized image element extra:map[boundingRect:map[bottom:554 height:231 left:0 right:412 top:323 width:412] lhId:page-1-IMG nodeLabel:A eukaryotic cell with the centrioles shown in yellow. © iStock path:1,HTML,1,BODY,1,DIV,7,DIV,0,DIV,2,DIV,0,MAIN,0,ARTICLE,0,DIV,3,DIV,0,DIV,0,DIV,0,PICTURE,5,IMG selector:div.list-group > div.fullwidth-teaser > picture > img snippet:<img decoding="async" src="https://actu.epfl.ch/image/163596/1440x810.jpg" aria-labelledby="background-label" alt="A eukaryotic cell with the centrioles shown in yellow. © iStock"> type:node]]] type:subitems]]]

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Est Savings
www.epfl.ch/fonts/SuisseIntl-Regular-WebS.woff2	25 ms
www.epfl.ch/fonts/SuisseIntl-SemiBold-WebS.woff2	20 ms

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Resource Size	Est Savings
Vue aérienne de l'EPFL © Jamani Caillet / EPFL, 2022 `div.container-full > div.fullwidth-teaser > figure.cover > img`	/wp-content/uploads/2022/12/EPFL-vue-aerienne-Jamani-Cail...	347.2 KiB	299.6 KiB
A eukaryotic cell with the centrioles shown in yellow. © iStock `div.list-group > div.fullwidth-teaser > picture > img`	actu.epfl.ch/image/163596/1440x810.jpg	311.9 KiB	264.4 KiB
Portrait d'Anna Fontcuverta i Morral - 2026 EPFL/Mediacom - CC-BY-SA 4.0 `div.card > a.card-img-top > picture > img.img-fluid`	www.epfl.ch/wp-content/uploads/2026/04/Anna-Fontcuberta-i-Morral-768x432.jpg	57.8 KiB	17.7 KiB
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32970/509x286.jpg	38.5 KiB	14.8 KiB
Couverture du numéro 20 du magazine Dimensions. Un enfant sur un tricycle trave… `div.card > a.card-img-top > picture > img.img-fluid`	www.epfl.ch/wp-content/uploads/2026/03/dimensions-num20-flipbook-768x432.jpg	49.7 KiB	12.8 KiB
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32754/509x286.jpg	36.0 KiB	12.3 KiB
Ig Nobel `a.card > div.card-body > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32144/509x286.jpg	31.1 KiB	7.5 KiB
Finale suisse MT180. Graphisme: Laura Persat `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32730/509x286.jpg	30.8 KiB	7.1 KiB
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32071/509x286.jpg	28.5 KiB	4.8 KiB
An atom `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Recherche.png	5.0 KiB	4.1 KiB

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

lhId: page-1-IMG

nodeLabel: A eukaryotic cell with the centrioles shown in yellow. © iStock

path: 1,HTML,1,BODY,1,DIV,7,DIV,0,DIV,2,DIV,0,MAIN,0,ARTICLE,0,DIV,3,DIV,0,DIV,0,DIV,0,PICTURE,5,IMG

selector: div.list-group > div.fullwidth-teaser > picture > img

snippet: <img decoding="async" src="https://actu.epfl.ch/image/163596/1440x810.jpg" aria-labelledby="background-label" alt="A eukaryotic cell with the centrioles shown in yellow. © iStock">

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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

value: No additional origins are good candidates for preconnecting

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size	Duration
www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1	84.5 KiB	600 ms
cdnjs.cloudflare.com/ajax/libs/jquery/3.7.1/jquery.min.js?ver=1776380526	27.5 KiB	947 ms
/wp-content/themes/wp-theme-2018/assets/css/elements.min....	52.3 KiB	600 ms
/wp-content/plugins/wp-gutenberg-epfl/frontend/lib/list.m...	7.2 KiB	150 ms
www.epfl.ch/wp-includes/js/jquery/jquery-migrate.js?ver=3.4.1	11.3 KiB
/wp-content/plugins/wp-gutenberg-epfl/build/style-index.c...	2.1 KiB
/wp-content/plugins/enlighter/cache/enlighterjs.min.css?v...	10.2 KiB	150 ms
/wp-content/plugins/flowpaper-lite-pdf-flipbook/assets/li...	3.9 KiB
/wp-content/themes/wp-theme-2018/assets/css/vendors.min.c...	7.7 KiB	150 ms
www.epfl.ch/wp-content/themes/wp-theme-2018/theme/style.min.css?ver=1776380526	2.0 KiB
www.epfl.ch/wp-content/themes/wp-theme-2018/style.css?ver=1776380526	1.4 KiB

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

Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 2.0 s

URL	Time Spent
epfl.ch/	1.2 s
www.epfl.ch/	780 ms
www.epfl.ch/en/	0.0 ms

These are the largest layout shifts observed on the page. Each table item represents a single layout shift, and shows the element that shifted the most. Below each item are possible root causes that led to the layout shift. Some of these layout shifts may not be included in the CLS metric value due to windowing. Learn how to improve CLS

Why this matters

Performance issues directly impact user engagement and conversion rates.

Element	Layout shift score
Lighting up the organizers of the cell's architecture NewsResearch Scientists … `div.container-full > div.list-group > div.fullwidth-teaser > div.fullwidth-teaser-text`	0.146

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Diagnostics

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 320 ms 50.5 KiB

URL	Transfer Size	Est Savings
www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1	83.5 KiB	42.7 KiB
www.epfl.ch/wp-includes/js/jquery/jquery-migrate.js?ver=3.4.1	10.2 KiB	4.2 KiB
www.epfl.ch/wp-includes/js/twemoji.js?ver=6.9.4	8.8 KiB	3.7 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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 320 ms 46.6 KiB

URL	Transfer Size	Est Savings
/wp-content/themes/wp-theme-2018/assets/css/elements.min....	51.3 KiB	46.6 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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 480 ms 248.3 KiB

URL	Transfer Size	Est Savings
www.googletagmanager.com/gtm.js?id=GTM-PJGBG5R	135.0 KiB	65.0 KiB
/wp-content/themes/wp-theme-2018/assets/js/vendors.min.js...	79.1 KiB	64.6 KiB
www.googletagmanager.com/gtag/js?id=G-N6BF9H5G73&cx=c&gtm=4e64h1	149.1 KiB	63.2 KiB
www.epfl.ch/wp-includes/js/jquery/jquery.js?ver=3.7.1	83.5 KiB	55.6 KiB

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work

Why this matters

Performance issues directly impact user engagement and conversion rates.

Category	Time Spent
Script Evaluation	758 ms
Other	682 ms
Style & Layout	395 ms
Script Parsing & Compilation	202 ms
Parse HTML & CSS	172 ms
Rendering	164 ms
Garbage Collection	28 ms

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL
Vue aérienne de l'EPFL © Jamani Caillet / EPFL, 2022 `div.container-full > div.fullwidth-teaser > figure.cover > img`	/wp-content/uploads/2022/12/EPFL-vue-aerienne-Jamani-Cail...
A eukaryotic cell with the centrioles shown in yellow. © iStock `div.list-group > div.fullwidth-teaser > picture > img`	actu.epfl.ch/image/163596/1440x810.jpg
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32754/509x286.jpg
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32071/509x286.jpg
Finale suisse MT180. Graphisme: Laura Persat `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32730/509x286.jpg
div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid `div.list-group-teaser-container > div.list-group-teaser-thumbnail > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32970/509x286.jpg
Ig Nobel `a.card > div.card-body > picture.card-img-top > img.img-fluid`	memento.epfl.ch/image/32144/509x286.jpg
Logo EPFL, École polytechnique fédérale de Lausanne `div#page > header.header > a.logo > img.img-fluid`	www.epfl.ch/wp-content/themes/wp-theme-2018/assets/svg/epfl-logo.svg
Logo of the EPFL `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2025/03/EPFL-logo.png
Schools and Colleges `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Facultes.png
Rolex Learning Center `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Campus.png
A person reading a book `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Education.png
An atom `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Recherche.png
A rocket `div.card-header > div.row > div.col-md-6 > img`	www.epfl.ch/wp-content/uploads/2021/09/Innovation.png

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

●Optimize DOM size

●Forced reflow

●LCP breakdown

●Modern HTTP

●Optimize viewport for mobile

●Minify CSS

●Avoids enormous network payloads Total size was 1,752 KiB

●User Timing marks and measures 5 user timings

●JavaScript execution time 0.9 s

●Avoid long main-thread tasks 10 long tasks found

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 160 ms

●Server Backend Latencies 630 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Initial server response time was short Root document took 20 ms

○INP breakdown

○Avoid non-composited animations

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.

Contrast

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Read more `div.fullwidth-teaser > div.fullwidth-teaser-text > div.fullwidth-teaser-footer > a.btn`
23.04.2026 `a.card > div.card-body > div.card-info > span.card-info-date`
18:00 `a.card > div.card-body > div.card-info > span.event-time`
20:00 `a.card > div.card-body > div.card-info > span.event-time`
Maps and directions `div.fullwidth-teaser > div.fullwidth-teaser-text > div.fullwidth-teaser-footer > a.btn`

These are opportunities to improve the legibility of your content.

Visible text labels that do not match the accessible name can result in a confusing experience for screen reader users. Learn more about accessible names.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Maps and directions `div.fullwidth-teaser > div.fullwidth-teaser-text > div.fullwidth-teaser-footer > a.btn`

○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

●`[role]` values are valid

●`[aria-*]` attributes have valid values

●`[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

●Elements use only permitted ARIA attributes

●Document has a `<title>` element

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

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

●Links have a discernible name

●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.

●Heading elements appear in a sequentially-descending order

●Document has a main landmark.

●Deprecated ARIA roles were not used

●Identical links have the same purpose.

○`[accesskey]` values are unique

○ARIA input fields have accessible names

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○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

○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

○Links are distinguishable without relying on color.

○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.

○`[lang]` attributes have a valid value

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

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

○All heading elements contain content.

○Uses ARIA roles only on compatible elements

○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

General

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

Why this matters

Performance issues directly impact user engagement and conversion rates.

Source	Description
www.epfl.ch/en/	`The Content-Security-Policy directive 'worker-src' contains the keyword 'none' alongside with other source expressions. The keyword 'none' must be the only source expression in the directive value, otherwise it is ignored.`
www.epfl.ch/en/	`The Content-Security-Policy directive 'worker-src' contains the keyword 'none' alongside with other source expressions. The keyword 'none' must be the only source expression in the directive value, otherwise it is ignored.`
www.epfl.ch/en/	`The Content-Security-Policy directive 'worker-src' contains the keyword 'none' alongside with other source expressions. The keyword 'none' must be the only source expression in the directive value, otherwise it is ignored.`

●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

●Serves images with appropriate resolution

●Page has the HTML doctype

●Properly defines charset

●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

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.

Content Best Practices

Descriptive link text helps search engines understand your content. Learn how to make links more accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Link destination	Link Text
actu.epfl.ch/news/lighting-up-the-organizers-of-the-cell-s-architect	Read more
www.epfl.ch/innovation/	Read more

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

Crawling and Indexing

Search engines may use `href` attributes on links to crawl websites. Ensure that the `href` attribute of anchor elements links to an appropriate destination, so more pages of the site can be discovered. Learn how to make links crawlable

Why this matters

Performance issues directly impact user engagement and conversion rates.

Uncrawlable Link
EN `nav.nav-lang > ul.dropdown-menu > li > a.active`

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

○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

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

●Document has a valid `rel=canonical`

○robots.txt is valid