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Lighthouse Mobile

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

Audit breakdown by category with detailed findings.

73

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.

RequestCache TTLTransfer Size
stackoverflow.com/Content/shared/chrome/chrome.css?v=764504b195d8604800.0 s98.9 KiB
/cdn-cgi/challenge-platform/h/b/scripts/jsd/0b8fb825cb67/...14400.0 s12.0 KiB
/avatar/10128c971dfa3ca3d89f471b693c9d72?s=36&d=identicon...300.0 s2.6 KiB
/avatar/f12a0330c5264e0c0872cf83898e0059?s=36&d=identicon...300.0 s2.4 KiB
/avatar/efdd0371ee7b983ab3b858ea92653aeb?s=36&d=identicon...300.0 s2.4 KiB
/avatar/9d36c6c0fe72160847d8aff404d9f1a0?s=36&d=identicon...300.0 s2.3 KiB
/avatar/96f5e5d858f1562ac8075c2664451b3b?s=36&d=identicon...300.0 s2.1 KiB
/avatar/d764dae6d3b6b39bc8ff40e28367d78a?s=36&d=identicon...300.0 s2.1 KiB
/avatar/8bfaa20f8775b87a2c0a6d9f4193ecbb?s=36&d=identicon...300.0 s2.0 KiB
/avatar/ab85c6b652a16b8135438e80cf480c48?s=36&d=identicon...300.0 s2.0 KiB
/avatar/df1d710f79509457b8603d60608772c8?s=36&d=identicon...300.0 s1.9 KiB
/avatar/168f7b509dd534671cb52c7ff58a6cf6?s=36&d=identicon...300.0 s1.7 KiB
/avatar/2a2941970f141aad669d13375dc57c4f?s=36&d=identicon...300.0 s1.6 KiB
cdn.sstatic.net/stackexchange/all.css?v=db31a2669ca3604800.0 s15.1 KiB
/avatar/e3887f18263b27e21575a5912b39a006?s=36&d=identicon...300.0 s1.6 KiB
/avatar/e301b767390b98cb298cd04ee196ac58?s=36&d=identicon...300.0 s1.6 KiB
/avatar/03508d221da4d3ebb99c724e19370b55?s=36&d=identicon...300.0 s1.6 KiB
/avatar/31f2b9cfa1cd901e508101b38d1af8ff?s=36&d=identicon...300.0 s1.5 KiB
/avatar/e8458cd805d568cfbc85636614d9d098?s=36&d=identicon...300.0 s1.5 KiB
/avatar/58c3cb5e1dac8d62442514f34ab84a0e?s=36&d=identicon...300.0 s1.3 KiB
/avatar/456b30a6c93001f930a726ff05217518?s=36&d=identicon...300.0 s1.3 KiB
/avatar/29221d8b990c741f510ddddcb67ec47e?s=36&d=identicon...300.0 s1.2 KiB
cdn.sstatic.net/stackexchange/Js/topbar.js?v=b2367277c351604800.0 s11.4 KiB
cdn.sstatic.net/stackexchange/Js/master.js?v=ef8b6ed08310604800.0 s10.4 KiB
/a-/AOh14GiU9JJ1lMC8Ux8lye9FUkCF46ri4wL2hfMtMERbNA=k-s3686400.0 s1.2 KiB
cdn.sstatic.net/stackexchange/Img/se-logo.png?v=8f7dca5b94db604800.0 s4.6 KiB
puzzling.stackexchange.com/Content/Sites/puzzling/Img/icon-48.png604800.0 s4.0 KiB
stackexchange.com/Content/Img/hero/bubble.png604800.0 s3.4 KiB
stackexchange.com/Content/Img/hero/check.png604800.0 s2.9 KiB
mathoverflow.net/Content/Sites/mathoverflow/Img/icon-48.png604800.0 s2.9 KiB
electronics.stackexchange.com/Content/Sites/electronics/Img/icon-48.png604800.0 s2.4 KiB
mathematica.stackexchange.com/Content/Sites/mathematica/Img/icon-48.png604800.0 s2.3 KiB
worldbuilding.stackexchange.com/Content/Sites/worldbuilding/Img/icon-48.png604800.0 s2.0 KiB
askubuntu.com/Content/Sites/askubuntu/Img/favicon.ico604800.0 s2.0 KiB
cdn.sstatic.net/stackexchange/Js/universal-login.js?v=30968200101f604800.0 s2.0 KiB
crafts.stackexchange.com/Content/Sites/crafts/Img/icon-48.png604800.0 s1.9 KiB
math.stackexchange.com/Content/Sites/math/Img/favicon.ico604800.0 s1.9 KiB
space.stackexchange.com/Content/Sites/space/Img/icon-48.png604800.0 s1.7 KiB
matheducators.stackexchange.com/Content/Sites/matheducators/Img/icon-48.png604800.0 s1.5 KiB
politics.stackexchange.com/Content/Sites/politics/Img/icon-48.png604800.0 s1.5 KiB
electronics.stackexchange.com/Content/Sites/electronics/Img/favicon.ico604800.0 s1.5 KiB
unix.stackexchange.com/Content/Sites/unix/Img/favicon.ico604800.0 s1.5 KiB
law.stackexchange.com/Content/Sites/law/Img/icon-48.png604800.0 s1.4 KiB
tex.stackexchange.com/Content/Sites/tex/Img/icon-48.png604800.0 s1.3 KiB
english.stackexchange.com/Content/Sites/english/Img/favicon.ico604800.0 s1.3 KiB
scifi.stackexchange.com/Content/Sites/scifi/Img/icon-48.png604800.0 s1.3 KiB
superuser.com/Content/Sites/superuser/Img/favicon.ico604800.0 s1.3 KiB
lh3.googleusercontent.com/a/ALm5wu2ZKm-HZQlbttbBrwGc1C9gtZ7Ij-K1hAqD9WhN=k-s3686400.0 s334 B
stackoverflow.com/Content/Sites/stackoverflow/Img/favicon.ico604800.0 s1.3 KiB
ru.stackoverflow.com/Content/Sites/ru/Img/favicon.ico604800.0 s1.2 KiB
superuser.com/Content/Sites/superuser/Img/icon-48.png604800.0 s1.2 KiB
serverfault.com/Content/Sites/serverfault/Img/favicon.ico604800.0 s1.1 KiB
stackexchange.com/Content/Img/hero/vote.png604800.0 s1.1 KiB
math.stackexchange.com/Content/Sites/math/Img/icon-48.png604800.0 s1.0 KiB
philosophy.stackexchange.com/Content/Sites/philosophy/Img/icon-48.png604800.0 s954 B
rpg.stackexchange.com/Content/Sites/rpg/Img/icon-48.png604800.0 s887 B
physics.stackexchange.com/Content/Sites/physics/Img/icon-48.png604800.0 s876 B
stackoverflow.com/Content/Sites/stackoverflow/Img/icon-48.png604800.0 s864 B
pm.stackexchange.com/Content/Sites/pm/Img/apple-touch-icon.png604800.0 s810 B
academia.stackexchange.com/Content/Sites/academia/Img/icon-48.png604800.0 s774 B
english.stackexchange.com/Content/Sites/english/Img/icon-48.png604800.0 s556 B
history.stackexchange.com/Content/Sites/history/Img/icon-48.png604800.0 s555 B
meta.stackexchange.com/Content/Sites/stackexchangemeta/Img/favicon.ico604800.0 s550 B
crypto.stackexchange.com/Content/Sites/crypto/Img/icon-48.png604800.0 s397 B
stackexchange.com/Content/Img/hero/close.png604800.0 s384 B

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.

URLTransfer SizeDuration
cdn.sstatic.net/stackexchange/Js/master.js?v=ef8b6ed0831010.4 KiB150 ms
cdn.sstatic.net/stackexchange/all.css?v=db31a2669ca315.1 KiB1.0 s
cdn.sstatic.net/stackexchange/Js/topbar.js?v=b2367277c35111.4 KiB150 ms
cdn.sstatic.net/stackexchange/Js/universal-login.js?v=30968200101f2.0 KiB
ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js30.4 KiB1.2 s
stackoverflow.com/Content/shared/chrome/chrome.css?v=764504b195d898.9 KiB1.7 s

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.

URLResource SizeEst Savings
Italian Philosopher div.module > div.userDetails > a > img.bar-sm
i.sstatic.net/xajrG.png?s=644.8 KiB4.3 KiB

Tap interactions may be delayed by up to 300 ms if the viewport is not optimized for mobile.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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

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.

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

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: 150 ms 10.5 KiB
URLTransfer SizeEst Savings
cdn.sstatic.net/stackexchange/Js/topbar.js?v=b2367277c35111.0 KiB5.3 KiB
cdn.sstatic.net/stackexchange/Js/master.js?v=ef8b6ed083109.9 KiB5.2 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: 560 ms 105.1 KiB
URLTransfer SizeEst Savings
stackoverflow.com/Content/shared/chrome/chrome.css?v=764504b195d898.1 KiB92.7 KiB
cdn.sstatic.net/stackexchange/all.css?v=db31a2669ca314.5 KiB12.4 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: 300 ms 20.4 KiB
URLTransfer SizeEst Savings
ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js29.8 KiB20.4 KiB

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
Voting arrows div.row > div > div.column > img
stackexchange.com/Content/Img/hero/vote.png
Speech bubbles div.row > div > div.column > img
stackexchange.com/Content/Img/hero/bubble.png
checkmark div.row > div > div.column > img
stackexchange.com/Content/Img/hero/check.png
close div.hero-box > div.close > a > img
stackexchange.com/Content/Img/hero/close.png

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

●Layout shift culprits
●Document request latency
●Optimize DOM size
●Font display
●Forced reflow
●LCP breakdown
●Modern HTTP
●Minify CSS
●Avoids enormous network payloads Total size was 340 KiB
●JavaScript execution time 0.6 s
●Minimizes main-thread work 1.8 s
●Avoid long main-thread tasks 7 long tasks found
●Page didn't prevent back/forward cache restoration
●Network Requests
●Network Round Trip Times 30 ms
●Server Backend Latencies 130 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
○INP breakdown
○LCP request discovery
○User Timing marks and measures
○Avoid non-composited animations
○Avoid large layout shifts
80

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

Some ARIA roles have required attributes that describe the state of the element to screen readers. Learn more about roles and required attributes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Search div.s-topbar--container > form#search > div.s-topbar--searchbar--input-group > input.s-input

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
hot div#mainArea > div.subheader > div.tabs > a.youarehere
4 answers | asked 10 hours ago by vsz on scifi div.question-container > div.question > div.metaInfo > span.va-middle
by vsz on div.question > div.metaInfo > span.va-middle > span.owner
4 answers | asked 13 hours ago by Erwann on tex div.question-container > div.question > div.metaInfo > span.va-middle
by Erwann on div.question > div.metaInfo > span.va-middle > span.owner
4 answers | asked 18 hours ago by pie on matheducators div.question-container > div.question > div.metaInfo > span.va-middle
by pie on div.question > div.metaInfo > span.va-middle > span.owner
2 answers | asked 22 hours ago by Rafał Mach on mathoverflow div.question-container > div.question > div.metaInfo > span.va-middle
by Rafał Mach on div.question > div.metaInfo > span.va-middle > span.owner
1 answers | asked 9 hours ago by RidiculousRichard on space div.question-container > div.question > div.metaInfo > span.va-middle
by RidiculousRichard on div.question > div.metaInfo > span.va-middle > span.owner
1 answers | asked 17 hours ago by honestSalami on history div.question-container > div.question > div.metaInfo > span.va-middle
by honestSalami on div.question > div.metaInfo > span.va-middle > span.owner
3 answers | asked 20 hours ago by Sebastiano on tex div.question-container > div.question > div.metaInfo > span.va-middle
by Sebastiano on div.question > div.metaInfo > span.va-middle > span.owner
2 answers | asked yesterday by Mike on rpg div.question-container > div.question > div.metaInfo > span.va-middle
by Mike on div.question > div.metaInfo > span.va-middle > span.owner
2 answers | asked yesterday by Italian Philosopher on politics div.question-container > div.question > div.metaInfo > span.va-middle
by Italian Philosopher on div.question > div.metaInfo > span.va-middle > span.owner
3 answers | asked 14 hours ago by Rio C on puzzling div.question-container > div.question > div.metaInfo > span.va-middle
by Rio C on div.question > div.metaInfo > span.va-middle > span.owner
1 answers | asked yesterday by Raj on scifi div.question-container > div.question > div.metaInfo > span.va-middle
by Raj on div.question > div.metaInfo > span.va-middle > span.owner
2 answers | asked 22 hours ago by karlh on tex div.question-container > div.question > div.metaInfo > span.va-middle
by karlh on div.question > div.metaInfo > span.va-middle > span.owner
2 answers | asked 21 hours ago by TomY on physics div.question-container > div.question > div.metaInfo > span.va-middle
by TomY on div.question > div.metaInfo > span.va-middle > span.owner
2 answers | asked 18 hours ago by Trevor on english div.question-container > div.question > div.metaInfo > span.va-middle
by Trevor on div.question > div.metaInfo > span.va-middle > span.owner
2 answers | asked 9 hours ago by Zachary Barbanell on crypto div.question-container > div.question > div.metaInfo > span.va-middle
by Zachary Barbanell on div.question > div.metaInfo > span.va-middle > span.owner
3 answers | asked 22 hours ago by Alma Arjuna on math div.question-container > div.question > div.metaInfo > span.va-middle
by Alma Arjuna on div.question > div.metaInfo > span.va-middle > span.owner
2 answers | asked yesterday by Rajorshi Chattopadhyay on academia div.question-container > div.question > div.metaInfo > span.va-middle
by Rajorshi Chattopadhyay on div.question > div.metaInfo > span.va-middle > span.owner
1 answers | asked 12 hours ago by robertspierre on superuser div.question-container > div.question > div.metaInfo > span.va-middle
by robertspierre on div.question > div.metaInfo > span.va-middle > span.owner
6 answers | asked Apr 18 at 15:36 by Dmyt on worldbuilding div.question-container > div.question > div.metaInfo > span.va-middle
by Dmyt on div.question > div.metaInfo > span.va-middle > span.owner
2 answers | asked yesterday by Mike on rpg div.question-container > div.question > div.metaInfo > span.va-middle
by Mike on div.question > div.metaInfo > span.va-middle > span.owner
2 answers | asked yesterday by Jay Bee on space div.question-container > div.question > div.metaInfo > span.va-middle
by Jay Bee on div.question > div.metaInfo > span.va-middle > span.owner
2 answers | asked 18 hours ago by Student_Number_249812341 on physics div.question-container > div.question > div.metaInfo > span.va-middle
by Student_Number_249812341 on div.question > div.metaInfo > span.va-middle > span.owner
4 answers | asked 2 days ago by qwerty on mathematica div.question-container > div.question > div.metaInfo > span.va-middle
by qwerty on div.question > div.metaInfo > span.va-middle > span.owner
7 answers | asked 2 days ago by Alex on electronics div.question-container > div.question > div.metaInfo > span.va-middle
by Alex on div.question > div.metaInfo > span.va-middle > span.owner
1 answers | asked 23 hours ago by Howard Hinnant on stackoverflow div.question-container > div.question > div.metaInfo > span.va-middle
by Howard Hinnant on div.question > div.metaInfo > span.va-middle > span.owner
2 answers | asked yesterday by dsollen on law div.question-container > div.question > div.metaInfo > span.va-middle
by dsollen on div.question > div.metaInfo > span.va-middle > span.owner
9 answers | asked 2 days ago by Syed on philosophy div.question-container > div.question > div.metaInfo > span.va-middle
by Syed on div.question > div.metaInfo > span.va-middle > span.owner
4 answers | asked 2 days ago by Rean on academia div.question-container > div.question > div.metaInfo > span.va-middle
by Rean on div.question > div.metaInfo > span.va-middle > span.owner
2 answers | asked 15 hours ago by Vincent on tex div.question-container > div.question > div.metaInfo > span.va-middle
by Vincent on div.question > div.metaInfo > span.va-middle > span.owner
2 answers | asked 20 hours ago by Joseph Rose on crafts div.question-container > div.question > div.metaInfo > span.va-middle
by Joseph Rose on div.question > div.metaInfo > span.va-middle > span.owner
per page div#mainArea > div#question-list > div.page-sizer > span.page-numbers
6.5k div.featured-site > div.site-stats > div.stats-container > div.stats
20k div.featured-site > div.site-stats > div.stats-container > div.stats
97% div.featured-site > div.site-stats > div.stats-container > div.stats
hot questions feed section#content > div.contentWrapper > div#feed-link > a
About div.site-footer--col > ul.-list > li > a.js-gps-track
Contact div.site-footer--col > ul.-list > li > a.js-gps-track
Feedback div.site-footer--col > ul.-list > li > a.js-gps-track
Stack Overflow div.site-footer--col > ul.-list > li > a.js-gps-track
Stack Internal div.site-footer--col > ul.-list > li > a.js-gps-track
Stack Data Licensing div.site-footer--col > ul.-list > li > a.js-gps-track
Stack Ads div.site-footer--col > ul.-list > li > a.js-gps-track
Press div.site-footer--col > ul.-list > li > a.js-gps-track
Legal div.site-footer--col > ul.-list > li > a.js-gps-track
Privacy Policy div.site-footer--col > ul.-list > li > a.js-gps-track
Terms of Service div.site-footer--col > ul.-list > li > a.js-gps-track
Cookie Settings div.site-footer--col > ul.-list > li#consent-footer-link > button.s-btn
Cookie Policy div.site-footer--col > ul.-list > li > a.js-gps-track
Technology div > ul.-list > li > a.-link
Culture & recreation div > ul.-list > li > a.-link
Life & arts div > ul.-list > li > a.-link
Science div > ul.-list > li > a.-link
Professional div > ul.-list > li > a.-link
Business div > ul.-list > li > a.-link
API div > ul.-list > li.mt16 > a.-link
Data div > ul.-list > li > a.-link
Blog div.site-footer--copyright > ul.-list > li > a.js-gps-track
Facebook div.site-footer--copyright > ul.-list > li > a.-link
Twitter div.site-footer--copyright > ul.-list > li > a.-link
LinkedIn div.site-footer--copyright > ul.-list > li > a.-link
Instagram div.site-footer--copyright > ul.-list > li > a.-link
Site design / logo © 2026 Stack Exchange Inc; div.site-footer--container > div.site-footer--copyright > p.md:mb0 > span
user contributions licensed under div.site-footer--container > div.site-footer--copyright > p.md:mb0 > span
CC BY-SA div.site-footer--container > div.site-footer--copyright > p.md:mb0 > a.-link
rev 2026.4.21.42306 div.site-footer--container > div.site-footer--copyright > p.md:mb0 > span#svnrev

These are opportunities to improve the legibility of your content.

Navigation

Properly ordered headings that do not skip levels convey the semantic structure of the page, making it easier to navigate and understand when using assistive technologies. Learn more about heading order.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Stack Exchange Q&A communities are different. Here's how: div.hero-box > div.row > div.text > h3.title
STACK EXCHANGE div.site-footer--container > nav.site-footer--nav > div.site-footer--col > h5.-title

These are opportunities to improve keyboard navigation in your application.

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.wrapper > header.s-topbar > div.s-topbar--container > a.s-topbar--logo div.wrapper > header.s-topbar > div.s-topbar--container > a.s-topbar--logo

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.

Tables and lists

Screen readers require list items (`<li>`) to be contained within a parent `<ul>`, `<ol>` or `<menu>` to be announced properly. Learn more about proper list structure.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Tour header.s-topbar > div.s-topbar--container > ol.s-navigation > li
About Us header.s-topbar > div.s-topbar--container > ol.s-navigation > li
Meta header.s-topbar > div.s-topbar--container > ol.s-navigation > li

These are opportunities to improve the experience of reading tabular or list data using assistive technology, like a screen reader.

Best practices

One main landmark helps screen reader users navigate a web page. Learn more about landmarks.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
html html

These items highlight common accessibility best practices.

○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]` 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
●ARIA attributes are used as specified for the element's role
●`[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 are distinguishable without relying on color.
●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
●Touch targets have sufficient size and spacing.
●Skip links are focusable.
●Deprecated ARIA roles were not used
●Uses ARIA roles only on compatible elements
●Image elements do not have `[alt]` attributes that are redundant text.
●Identical links have the same purpose.
○`[accesskey]` values are unique
○`button`, `link`, and `menuitem` elements have accessible names
○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.
○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
○The document does not use `<meta http-equiv="refresh">`
○`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
○`<object>` elements have alternate text
○Select elements have associated label elements.
○No element has a `[tabindex]` value greater than 0
○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.
○Elements with visible text labels have matching accessible names.
○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.
77

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLDisplayed sizeActual sizeExpected size
Voting arrows div.row > div > div.column > img
stackexchange.com/Content/Img/hero/vote.png141 x 86141 x 86212 x 129
Speech bubbles div.row > div > div.column > img
stackexchange.com/Content/Img/hero/bubble.png107 x 86107 x 86161 x 129
checkmark div.row > div > div.column > img
stackexchange.com/Content/Img/hero/check.png90 x 8690 x 86135 x 129
Dmyt div.module > div.userDetails > a > img.bar-sm
/avatar/03508d221da4d3ebb99c724e19370b55?s=36&d=identicon...30 x 3030 x 3045 x 45
Rean div.module > div.userDetails > a > img.bar-sm
/avatar/10128c971dfa3ca3d89f471b693c9d72?s=36&d=identicon...30 x 3030 x 3045 x 45
Sebastiano div.module > div.userDetails > a > img.bar-sm
/avatar/168f7b509dd534671cb52c7ff58a6cf6?s=36&d=identicon...30 x 3030 x 3045 x 45
Rio C div.module > div.userDetails > a > img.bar-sm
/avatar/29221d8b990c741f510ddddcb67ec47e?s=36&d=identicon...30 x 3030 x 3045 x 45
Howard Hinnant div.module > div.userDetails > a > img.bar-sm
/avatar/2a2941970f141aad669d13375dc57c4f?s=36&d=identicon...30 x 3030 x 3045 x 45
Alex div.module > div.userDetails > a > img.bar-sm
/avatar/31f2b9cfa1cd901e508101b38d1af8ff?s=36&d=identicon...30 x 3030 x 3045 x 45
Rajorshi Chattopadhyay div.module > div.userDetails > a > img.bar-sm
/avatar/456b30a6c93001f930a726ff05217518?s=36&d=identicon...30 x 3030 x 3045 x 45
Alma Arjuna div.module > div.userDetails > a > img.bar-sm
/avatar/58c3cb5e1dac8d62442514f34ab84a0e?s=36&d=identicon...30 x 3030 x 3045 x 45
Zachary Barbanell div.module > div.userDetails > a > img.bar-sm
/avatar/8bfaa20f8775b87a2c0a6d9f4193ecbb?s=36&d=identicon...30 x 3030 x 3045 x 45
vsz div.module > div.userDetails > a > img.bar-sm
/avatar/96f5e5d858f1562ac8075c2664451b3b?s=36&d=identicon...30 x 3030 x 3045 x 45
qwerty div.module > div.userDetails > a > img.bar-sm
/avatar/9d36c6c0fe72160847d8aff404d9f1a0?s=36&d=identicon...30 x 3030 x 3045 x 45
Vincent div.module > div.userDetails > a > img.bar-sm
/avatar/ab85c6b652a16b8135438e80cf480c48?s=36&d=identicon...30 x 3030 x 3045 x 45
robertspierre div.module > div.userDetails > a > img.bar-sm
/avatar/d764dae6d3b6b39bc8ff40e28367d78a?s=36&d=identicon...30 x 3030 x 3045 x 45
Mike div.module > div.userDetails > a > img.bar-sm
/avatar/df1d710f79509457b8603d60608772c8?s=36&d=identicon...30 x 3030 x 3045 x 45
TomY div.module > div.userDetails > a > img.bar-sm
/avatar/e301b767390b98cb298cd04ee196ac58?s=36&d=identicon...30 x 3030 x 3045 x 45
Erwann div.module > div.userDetails > a > img.bar-sm
/avatar/e3887f18263b27e21575a5912b39a006?s=36&d=identicon...30 x 3030 x 3045 x 45
Raj div.module > div.userDetails > a > img.bar-sm
/avatar/e8458cd805d568cfbc85636614d9d098?s=36&d=identicon...30 x 3030 x 3045 x 45
dsollen div.module > div.userDetails > a > img.bar-sm
/avatar/efdd0371ee7b983ab3b858ea92653aeb?s=36&d=identicon...30 x 3030 x 3045 x 45
Syed div.module > div.userDetails > a > img.bar-sm
/avatar/f12a0330c5264e0c0872cf83898e0059?s=36&d=identicon...30 x 3030 x 3045 x 45
Jay Bee div.module > div.userDetails > a > img.bar-sm
/a-/AOh14GiU9JJ1lMC8Ux8lye9FUkCF46ri4wL2hfMtMERbNA=k-s3630 x 3036 x 3645 x 45
Trevor div.module > div.userDetails > a > img.bar-sm
lh3.googleusercontent.com/a/ALm5wu2ZKm-HZQlbttbBrwGc1C9gtZ7Ij-K1hAqD9WhN=k-s3630 x 3036 x 3645 x 45
close div.hero-box > div.close > a > img
stackexchange.com/Content/Img/hero/close.png11 x 1111 x 1117 x 17

General

Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Deprecation / WarningSource
SharedStorage
stackexchange.com/cdn-cgi/challenge-platform/scripts/jsd/main.js
StorageType.persistent is deprecated. Please use standardized navigator.storage instead.
stackexchange.com/cdn-cgi/challenge-platform/scripts/jsd/main.js
Fledge
stackexchange.com/cdn-cgi/challenge-platform/scripts/jsd/main.js
●Uses HTTPS
●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
91

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 destinationLink Text
stackexchange.com/tourLearn more

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 are crawlable
●Image elements have `[alt]` attributes
●Document has a valid `hreflang`
○robots.txt is valid
○Document has a valid `rel=canonical`

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