https://www.ox.ac.uk
Lighthouse Desktop
· 0 checks — Desktop Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.SCORE
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GRADE
FIX
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REVIEW
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PASS
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INFO
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Detailed Report
Audit breakdown by category with detailed findings.
88
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.
A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.
Why this matters
Performance issues directly impact user engagement and conversion rates.
headings: [map[key:source label:Top function call valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:86.841 source:map[column:640 line:4 type:source-location url:https://www.ox.ac.uk/sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB9bfVJ_3N7-eC3gKeS-sI__ATnX8WF8ltra-g2RmFaF163qjG6u_xdvxVSENyHJmQk__h7T-cjtV_dUO9EYp5xzvQZuTpmuCIt2rzPKmYSUARw8.js urlProvider:network]]]
headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:30.393 source:map[column:30882 line:3 type:source-location url:https://www.ox.ac.uk/sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB9bfVJ_3N7-eC3gKeS-sI__ATnX8WF8ltra-g2RmFaF163qjG6u_xdvxVSENyHJmQk__h7T-cjtV_dUO9EYp5xzvQZuTpmuCIt2rzPKmYSUARw8.js urlProvider:network]] map[reflowTime:0.648 source:map[column:30979 line:3 type:source-location url:https://www.ox.ac.uk/sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB9bfVJ_3N7-eC3gKeS-sI__ATnX8WF8ltra-g2RmFaF163qjG6u_xdvxVSENyHJmQk__h7T-cjtV_dUO9EYp5xzvQZuTpmuCIt2rzPKmYSUARw8.js urlProvider:network]] map[reflowTime:0.438 source:map[column:31260 line:3 type:source-location url:https://www.ox.ac.uk/sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB9bfVJ_3N7-eC3gKeS-sI__ATnX8WF8ltra-g2RmFaF163qjG6u_xdvxVSENyHJmQk__h7T-cjtV_dUO9EYp5xzvQZuTpmuCIt2rzPKmYSUARw8.js urlProvider:network]] map[reflowTime:0.099 source:map[column:31351 line:3 type:source-location url:https://www.ox.ac.uk/sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB9bfVJ_3N7-eC3gKeS-sI__ATnX8WF8ltra-g2RmFaF163qjG6u_xdvxVSENyHJmQk__h7T-cjtV_dUO9EYp5xzvQZuTpmuCIt2rzPKmYSUARw8.js urlProvider:network]] map[reflowTime:0.188 source:map[column:31632 line:3 type:source-location url:https://www.ox.ac.uk/sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB9bfVJ_3N7-eC3gKeS-sI__ATnX8WF8ltra-g2RmFaF163qjG6u_xdvxVSENyHJmQk__h7T-cjtV_dUO9EYp5xzvQZuTpmuCIt2rzPKmYSUARw8.js urlProvider:network]] map[reflowTime:0.253 source:map[column:31782 line:3 type:source-location url:https://www.ox.ac.uk/sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB9bfVJ_3N7-eC3gKeS-sI__ATnX8WF8ltra-g2RmFaF163qjG6u_xdvxVSENyHJmQk__h7T-cjtV_dUO9EYp5xzvQZuTpmuCIt2rzPKmYSUARw8.js urlProvider:network]] map[reflowTime:0.304 source:map[column:31900 line:3 type:source-location url:https://www.ox.ac.uk/sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB9bfVJ_3N7-eC3gKeS-sI__ATnX8WF8ltra-g2RmFaF163qjG6u_xdvxVSENyHJmQk__h7T-cjtV_dUO9EYp5xzvQZuTpmuCIt2rzPKmYSUARw8.js urlProvider:network]] map[reflowTime:0.617 source:map[column:41 line:1066 type:source-location url:https://www.ox.ac.uk/sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB9bfVJ_3N7-eC3gKeS-sI__ATnX8WF8ltra-g2RmFaF163qjG6u_xdvxVSENyHJmQk__h7T-cjtV_dUO9EYp5xzvQZuTpmuCIt2rzPKmYSUARw8.js urlProvider:network]] map[reflowTime:25.771 source:map[column:5688 line:5 type:source-location url:https://www.ox.ac.uk/sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB9bfVJ_3N7-eC3gKeS-sI__ATnX8WF8ltra-g2RmFaF163qjG6u_xdvxVSENyHJmQk__h7T-cjtV_dUO9EYp5xzvQZuTpmuCIt2rzPKmYSUARw8.js urlProvider:network]] map[reflowTime:3.629 source:map[column:26533 line:5 type:source-location url:https://www.ox.ac.uk/sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB9bfVJ_3N7-eC3gKeS-sI__ATnX8WF8ltra-g2RmFaF163qjG6u_xdvxVSENyHJmQk__h7T-cjtV_dUO9EYp5xzvQZuTpmuCIt2rzPKmYSUARw8.js urlProvider:network]] map[reflowTime:20.152 source:map[column:6794 line:5 type:source-location url:https://www.ox.ac.uk/sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB9bfVJ_3N7-eC3gKeS-sI__ATnX8WF8ltra-g2RmFaF163qjG6u_xdvxVSENyHJmQk__h7T-cjtV_dUO9EYp5xzvQZuTpmuCIt2rzPKmYSUARw8.js urlProvider:network]] map[reflowTime:3.442 source:map[column:3774 line:5 type:source-location url:https://www.ox.ac.uk/sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB9bfVJ_3N7-eC3gKeS-sI__ATnX8WF8ltra-g2RmFaF163qjG6u_xdvxVSENyHJmQk__h7T-cjtV_dUO9EYp5xzvQZuTpmuCIt2rzPKmYSUARw8.js urlProvider:network]] map[reflowTime:0.427 source:map[column:3796 line:5 type:source-location url:https://www.ox.ac.uk/sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB9bfVJ_3N7-eC3gKeS-sI__ATnX8WF8ltra-g2RmFaF163qjG6u_xdvxVSENyHJmQk__h7T-cjtV_dUO9EYp5xzvQZuTpmuCIt2rzPKmYSUARw8.js urlProvider:network]] map[reflowTime:0.48 source:map[column:28444 line:5 type:source-location url:https://www.ox.ac.uk/sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB9bfVJ_3N7-eC3gKeS-sI__ATnX8WF8ltra-g2RmFaF163qjG6u_xdvxVSENyHJmQk__h7T-cjtV_dUO9EYp5xzvQZuTpmuCIt2rzPKmYSUARw8.js urlProvider:network]]]
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 | |
|---|---|---|---|
Two students sitting outside in college div.field > span.field-item-single > div.ds-1col > img | /sites/files/oxford/styles/ow_large_feature/s3/bcar_ug_tw... | 188.6 KiB | 86.7 KiB |
Group of current student in quad ul.study-group-two > li.study-type > a > img.media-element | www.ox.ac.uk/sites/files/oxford/st_ox_current5.jpg | 40.9 KiB | 28.6 KiB |
Old magazine div.link-block-bgimage-wrapper > div.field > span.field-item-single > img | /sites/files/oxford/styles/ow_small_highlight/s3/disc_reu... | 29.3 KiB | 20.5 KiB |
Undergrad students 3 ul.study-group-one > li.study-type > a > img.media-element | www.ox.ac.uk/sites/files/oxford/st_ox_undergrad3.jpg | 32.0 KiB | 19.7 KiB |
Grad students 2 ul.study-group-one > li.study-type > a > img.media-element | www.ox.ac.uk/sites/files/oxford/st_ox_grad2.jpg | 30.5 KiB | 18.2 KiB |
Array of food div.link-block-bgimage-wrapper > div.field > span.field-item-single > img | /sites/files/oxford/styles/ow_small_highlight/s3/disc_oed... | 25.8 KiB | 17.1 KiB |
Eggs illustration div.link-block-bgimage-wrapper > div.field > span.field-item-single > img | /sites/files/oxford/styles/ow_small_highlight/s3/disc_nat... | 24.7 KiB | 15.9 KiB |
Greek frieze div.link-block-bgimage-wrapper > div.field > span.field-item-single > img | /sites/files/oxford/styles/ow_small_highlight/s3/disc_oup... | 23.2 KiB | 14.4 KiB |
Oxplore equality div.link-block-bgimage-wrapper > div.field > span.field-item-single > img | /sites/files/oxford/styles/ow_small_highlight/s3/disc_oxp... | 21.2 KiB | 12.4 KiB |
F1 car speeding by div.link-block-bgimage-wrapper > div.field > span.field-item-single > img | /sites/files/oxford/styles/ow_small_highlight/s3/disc_spa... | 17.4 KiB | 8.6 KiB |
Oxford skyline in black and white div.link-block-bgimage-wrapper > div.field > span.field-item-single > img | /sites/files/oxford/styles/ow_small_highlight/s3/disc_oxf... | 17.2 KiB | 8.4 KiB |
Kids in a museum div.link-block-bgimage-wrapper > div.field > span.field-item-single > img | /sites/files/oxford/styles/ow_small_highlight/s3/disc_his... | 16.0 KiB | 7.3 KiB |
woman reading div.link-block-bgimage-wrapper > div.field > span.field-item-single > img | /sites/files/oxford/styles/ow_small_highlight/s3/disc_con... | 15.7 KiB | 7.2 KiB |
Teenagers on mobile phones. Credit: Drazen Zigic, Getty Images div.link-block-bgimage-wrapper > div.field > span.field-item-single > img | /sites/files/oxford/styles/ow_listing/s3/field/field_imag... | 14.8 KiB | 5.9 KiB |
Solar farm in Africa div.link-block-bgimage-wrapper > div.field > span.field-item-single > img | /sites/files/oxford/styles/ow_small_highlight/s3/disc_odi... | 12.6 KiB | 5.8 KiB |
podcast human interface div.link-block-bgimage-wrapper > div.field > span.field-item-single > img | /sites/files/oxford/styles/ow_small_highlight/s3/disc_pod... | 12.5 KiB | 5.7 KiB |
Oxford's women claim victory in the 2026 Boat Race div.link-block-bgimage-wrapper > div.field > span.field-item-single > img | /sites/files/oxford/styles/ow_listing/s3/field/field_imag... | 14.5 KiB | 5.5 KiB |
Adult students in a seminar ul.study-group-two > li.study-type > a > img.media-element | www.ox.ac.uk/sites/files/oxford/st_ox_conted6.jpg | 17.5 KiB | 5.2 KiB |
Space trash div.link-block-bgimage-wrapper > div.field > span.field-item-single > img | /sites/files/oxford/styles/ow_small_highlight/s3/disc_qua... | 10.2 KiB | 4.7 KiB |
Artistic illustration depicting an ocean between 554 and 539 million years ago.… div.link-block-bgimage-wrapper > div.field > span.field-item-single > img | /sites/files/oxford/styles/ow_listing/s3/field/field_imag... | 12.2 KiB | 4.0 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-0-IMG
nodeLabel: Two students sitting outside in college
path: 1,HTML,1,BODY,3,SECTION,1,SECTION,0,DIV,0,DIV,0,SECTION,0,SECTION,1,DIV,0,DIV,0,DIV,1,DIV,0,DIV,0,DIV,0,DIV,0,A,0,DIV,0,DIV,0,SPAN,0,DIV,0,IMG
selector: div.field > span.field-item-single > div.ds-1col > img
snippet: <img typeof="foaf:Image" src="https://www.ox.ac.uk/sites/files/oxford/styles/ow_large_feature/s3/bcar_ug…" width="1600" height="550" alt="Two students sitting outside in college">
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
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 |
|---|---|---|
| /sites/files/oxford/advagg_js/js__9q_RhUzRB9SYU1-amhF7x_i... | 46.5 KiB | 193 ms |
| /sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB... | 44.9 KiB | 293 ms |
| /sites/files/oxford/advagg_js/js__z5ONFBC5kmHZRZuHWswENYj... | 9.6 KiB | 92 ms |
| /sites/files/oxford/advagg_js/js__g6HAL4XtohiHzS9CG4SIugq... | 12.5 KiB | 143 ms |
| /sites/files/oxford/advagg_js/js__9o6MTP80DXWHri8ze4nKy9q... | 1.1 KiB | 92 ms |
| /sites/files/oxford/advagg_css/css__WcyGoWryerB6FTiefeluO... | 12.5 KiB | 143 ms |
| /sites/files/oxford/advagg_css/css__MarV35vNLf0_XPV9JUJLb... | 36.7 KiB | 343 ms |
| /sites/files/oxford/advagg_css/css__Oz20qOQtvbB-9QPNXbkEm... | 1.3 KiB | 193 ms |
| /sites/files/oxford/advagg_css/css__spdjcEZR5oB7JDp-aKZkg... | 5.0 KiB | 193 ms |
| /sites/files/oxford/advagg_css/css__UY0etF999x6scvHTvffNH... | 1.3 KiB | 193 ms |
| /sites/files/oxford/advagg_css/css__OyUP6r6gWDd7g9HyyAPkK... | 1.9 KiB | 193 ms |
| /sites/files/oxford/advagg_css/css__BJ6Ou6QsBRtnFTmxaakam... | 2.6 KiB | 92 ms |
These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.
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: 40 ms 32.7 KiB
| URL | Transfer Size | Est Savings |
|---|---|---|
| /sites/files/oxford/advagg_js/js__9q_RhUzRB9SYU1-amhF7x_i... | 46.0 KiB | 13.4 KiB |
| /sites/files/oxford/advagg_js/js__ihdwYz7z62m5viS1EMhNOpB... | 44.4 KiB | 9.6 KiB |
| /sites/files/oxford/advagg_js/js__z5ONFBC5kmHZRZuHWswENYj... | 9.2 KiB | 5.7 KiB |
| /sites/files/oxford/advagg_js/js__g6HAL4XtohiHzS9CG4SIugq... | 12.0 KiB | 4.0 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.
Why this matters
Performance issues directly impact user engagement and conversion rates.
Estimated savings: 40 ms 43.9 KiB
| URL | Transfer Size | Est Savings |
|---|---|---|
| /sites/files/oxford/advagg_css/css__MarV35vNLf0_XPV9JUJLb... | 36.2 KiB | 32.0 KiB |
| /sites/files/oxford/advagg_css/css__WcyGoWryerB6FTiefeluO... | 12.0 KiB | 12.0 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: 120 ms 148.7 KiB
| URL | Transfer Size | Est Savings |
|---|---|---|
| www.googletagmanager.com/gtm.js?id=GTM-TDB29T | 137.7 KiB | 66.1 KiB |
| cc.cdn.civiccomputing.com/9/cookieControl-9.x.min.js | 123.0 KiB | 57.1 KiB |
| /sites/files/oxford/advagg_js/js__9q_RhUzRB9SYU1-amhF7x_i... | 46.0 KiB | 25.5 KiB |
More information about the performance of your application. These numbers don't directly affect the Performance score.
●Time to Interactive 2.4 s
●Max Potential First Input Delay 120 ms
●Layout shift culprits
●Document request latency
●Optimize DOM size
●Font display
●LCP breakdown
●Modern HTTP
●Optimize viewport for mobile
●Minify CSS
●Avoids enormous network payloads Total size was 1,557 KiB
●JavaScript execution time 0.4 s
●Minimizes main-thread work 1.0 s
●Avoid long main-thread tasks 4 long tasks found
●Image elements have explicit `width` and `height`
●Page didn't prevent back/forward cache restoration
●Network Requests
●Network Round Trip Times 10 ms
●Server Backend Latencies 160 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 50 ms
●Avoid large layout shifts 1 layout shift found
○INP breakdown
○User Timing marks and measures
○Avoid non-composited animations
95
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.
Names and labels
When a button doesn't have an accessible name, screen readers announce it as "button", making it unusable for users who rely on screen readers. Learn how to make buttons more accessible.
Why this matters
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
div.field > div.field > span.field-item-single > button.carousel-next-btn div.field > div.field > span.field-item-single > button.carousel-next-btn |
div.field > div.field > span.field-item-single > button.carousel-prev-btn div.field > div.field > span.field-item-single > button.carousel-prev-btn |
div.field > span.field-item-single > div.ds-1col > button.toggle-icon div.field > span.field-item-single > div.ds-1col > button.toggle-icon |
div.field > span.field-item-single > div.ds-1col > button.toggle-icon div.field > span.field-item-single > div.ds-1col > button.toggle-icon |
div.field > span.field-item-single > div.ds-1col > button.toggle-icon div.field > span.field-item-single > div.ds-1col > button.toggle-icon |
div#node-oxweb-homepage-full-group-discover-carousel > div.field > span.field-item-single > button.carousel-next-btn div#node-oxweb-homepage-full-group-discover-carousel > div.field > span.field-item-single > button.carousel-next-btn |
div#node-oxweb-homepage-full-group-discover-carousel > div.field > span.field-item-single > button.carousel-prev-btn div#node-oxweb-homepage-full-group-discover-carousel > div.field > span.field-item-single > button.carousel-prev-btn |
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
●`[role]` values are valid
●`[aria-*]` attributes have valid values
●`[aria-*]` attributes are valid and not misspelled
●Image elements have `[alt]` attributes
●Input buttons have discernible text.
●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.
●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
●Background and foreground colors have a sufficient contrast ratio
●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
○`[accesskey]` values are unique
○`button`, `link`, and `menuitem` elements 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 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.
○Identical links have the same purpose.
○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.
81
Best Practices
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 / Warning | Source |
|---|---|
| AttributionReporting | |
| Topics |
●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
●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
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`