Skip to content
https://www.haskell.org

Lighthouse Mobile

· 0 checks — Mobile Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.
SCORE
0
GRADE
FIX
0
REVIEW
0
PASS
0
INFO
0

Detailed Report

Audit breakdown by category with detailed findings.

70

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
www.haskell.org/img/pattern.png0.0 ms291.6 KiB
www.haskell.org/img/haskell-uwu.png0.0 ms100.5 KiB
www.haskell.org/js/jquery.js0.0 ms33.3 KiB
www.haskell.org/fonts/ubuntu-mono-v15-latin-regular.woff20.0 ms27.0 KiB
www.haskell.org/testimonials/logos/mercury.png0.0 ms25.6 KiB
www.haskell.org/testimonials/logos/bellroy.png0.0 ms23.4 KiB
www.haskell.org/fonts/raleway-v28-latin-700.woff20.0 ms21.1 KiB
www.haskell.org/testimonials/logos/Scrive.png0.0 ms19.5 KiB
www.haskell.org/testimonials/logos/stackbuilders.png0.0 ms18.6 KiB
www.haskell.org/css/hl.css0.0 ms17.0 KiB
www.haskell.org/testimonials/logos/hubspot.png0.0 ms16.3 KiB
www.haskell.org/testimonials/logos/fission.png0.0 ms15.4 KiB
www.haskell.org/fonts/source-sans-3-v9-latin-regular.woff20.0 ms14.9 KiB
i1.ytimg.com/vi/t1e8gqXLbsU/mqdefault.jpg7200.0 s19.8 KiB
www.haskell.org/testimonials/logos/hasura.png0.0 ms14.6 KiB
www.haskell.org/testimonials/logos/e-bot7.png0.0 ms14.4 KiB
www.haskell.org/testimonials/logos/foxhoundsystems.png0.0 ms13.4 KiB
www.haskell.org/testimonials/logos/finn.png0.0 ms12.8 KiB
www.haskell.org/testimonials/logos/iohk.png0.0 ms11.2 KiB
www.haskell.org/testimonials/logos/noredink.png0.0 ms11.0 KiB
i1.ytimg.com/vi/LnX3B9oaKzw/mqdefault.jpg7200.0 s14.0 KiB
www.haskell.org/testimonials/logos/centralapp.png0.0 ms10.5 KiB
i1.ytimg.com/vi/4RuLzL_q0zs/mqdefault.jpg7200.0 s13.4 KiB
www.haskell.org/testimonials/logos/imagineai.png0.0 ms9.6 KiB
www.haskell.org/testimonials/logos/calabrio.png0.0 ms8.5 KiB
i1.ytimg.com/vi/re96UgMk6GQ/mqdefault.jpg7200.0 s10.9 KiB
www.haskell.org/js/bootstrap.min.js0.0 ms7.8 KiB
i1.ytimg.com/vi/WHVMjMIJnB4/mqdefault.jpg7200.0 s10.0 KiB
www.haskell.org/js/jquery.console.js0.0 ms7.2 KiB
www.haskell.org/js/tryhaskell.pages.js0.0 ms6.8 KiB
www.haskell.org/testimonials/logos/scarf.png0.0 ms5.9 KiB
www.haskell.org/testimonials/logos/bitnomial.png0.0 ms4.1 KiB
www.haskell.org/testimonials/logos/serokell.png0.0 ms3.6 KiB
www.haskell.org/js/tryhaskell.js0.0 ms2.8 KiB
www.haskell.org/img/haskell-logo.svg0.0 ms1.6 KiB
www.haskell.org/js/home.js0.0 ms777 B
www.haskell.org/css/fonts.css0.0 ms410 B
cdn.jsdelivr.net/npm/glider-js@1/glider.min.js604800.0 s3.2 KiB
cdn.jsdelivr.net/npm/glider-js@1/glider.min.css604800.0 s1.1 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:0.19693] map[node:map[boundingRect:map[bottom:805 height:43 left:30 right:381 top:762 width:351] lhId:page-24-SMALL nodeLabel:(click to insert) path:1,HTML,2,BODY,1,DIV,11,DIV,1,DIV,1,DIV,1,DIV,1,DIV,1,DIV,1,DIV,3,DIV,0,DIV,2,P,1,SMALL selector:div#guide > div.indent > p > small.note snippet:<small class="note"> type:node] score:0.119511 subItems:map[items:[map[cause:Web font extra:map[type:url value:https://www.haskell.org/fonts/source-sans-3-v9-latin-regular.woff2]] map[cause:Web font extra:map[type:url value:https://www.haskell.org/fonts/ubuntu-mono-v15-latin-regular.woff2]] map[cause:Web font extra:map[type:url value:https://www.haskell.org/fonts/raleway-v28-latin-700.woff2]]] type:subitems]] map[node:map[boundingRect:map[bottom:2167 height:1240 left:0 right:412 top:927 width:412] lhId:page-23-DIV nodeLabel:Why Haskell? A new paradigm Express your ideas clearly and learn a new way of … path:1,HTML,2,BODY,1,DIV,15,DIV selector:body.page-home > div.wrap > div.features snippet:<div class="features"> type:node] score:0.077419 subItems:map[items:[map[cause:Unsized image element extra:map[boundingRect:map[bottom:2358 height:93 left:20 right:186 top:2265 width:166] lhId:page-18-IMG nodeLabel:div.row > div.span3 > a.thumbnail > img.img-responsive path:1,HTML,2,BODY,1,DIV,17,DIV,1,DIV,1,DIV,1,DIV,1,DIV,5,DIV,1,DIV,1,DIV,1,DIV,1,A,1,IMG selector:div.row > div.span3 > a.thumbnail > img.img-responsive snippet:<img src="https://i1.ytimg.com/vi/re96UgMk6GQ/mqdefault.jpg" alt="" class="img-responsive"> type:node]]] type:subitems]]]

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:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:26.919 source:map[column:1098 line:15 type:source-location url:https://cdn.jsdelivr.net/npm/glider-js@1/glider.min.js urlProvider:network]] map[reflowTime:3.351 source:map[column:1599 line:15 type:source-location url:https://cdn.jsdelivr.net/npm/glider-js@1/glider.min.js urlProvider:network]] map[reflowTime:2.682 source:map[column:3768 line:15 type:source-location url:https://cdn.jsdelivr.net/npm/glider-js@1/glider.min.js urlProvider:network]] map[reflowTime:0.197 source:map[column:3950 line:15 type:source-location url:https://cdn.jsdelivr.net/npm/glider-js@1/glider.min.js urlProvider:network]] map[reflowTime:0.911 source:map[column:4532 line:15 type:source-location url:https://cdn.jsdelivr.net/npm/glider-js@1/glider.min.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.

URLResource SizeEst Savings
Sponsors Fastly's Next Generation CDN provides low latency access for all of H… body.page-home > div.wrap > div.sponsors
www.haskell.org/img/pattern.png291.1 KiB41.1 KiB
Mercury: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/mercury.png25.3 KiB23.7 KiB
Bellroy: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/bellroy.png23.2 KiB21.5 KiB
Scrive: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/Scrive.png19.3 KiB17.6 KiB
div.row > div.span3 > a.thumbnail > img.img-responsive div.row > div.span3 > a.thumbnail > img.img-responsive
i1.ytimg.com/vi/t1e8gqXLbsU/mqdefault.jpg19.7 KiB17.2 KiB
Stack Builders: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/stackbuilders.png18.4 KiB16.8 KiB
HubSpot: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/hubspot.png16.1 KiB14.5 KiB
Fission: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/fission.png15.2 KiB13.6 KiB
Hasura: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/hasura.png14.4 KiB12.8 KiB
e-bot7: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/e-bot7.png14.2 KiB12.6 KiB
Foxhound Systems: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/foxhoundsystems.png13.2 KiB11.7 KiB
div.row > div.span3 > a.thumbnail > img.img-responsive div.row > div.span3 > a.thumbnail > img.img-responsive
i1.ytimg.com/vi/LnX3B9oaKzw/mqdefault.jpg14.0 KiB11.4 KiB
finn.no: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/finn.png12.6 KiB11.2 KiB
div.row > div.span3 > a.thumbnail > img.img-responsive div.row > div.span3 > a.thumbnail > img.img-responsive
i1.ytimg.com/vi/4RuLzL_q0zs/mqdefault.jpg13.3 KiB10.8 KiB
IOHK: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/iohk.png11.0 KiB9.8 KiB
NoRedInk: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/noredink.png10.8 KiB9.6 KiB
CentralApp: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/centralapp.png10.2 KiB9.1 KiB
Imagine AI: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/imagineai.png9.4 KiB8.4 KiB
div.row > div.span3 > a.thumbnail > img.img-responsive div.row > div.span3 > a.thumbnail > img.img-responsive
i1.ytimg.com/vi/re96UgMk6GQ/mqdefault.jpg10.5 KiB7.9 KiB
div.row > div.span3 > a.thumbnail > img.img-responsive div.row > div.span3 > a.thumbnail > img.img-responsive
i1.ytimg.com/vi/WHVMjMIJnB4/mqdefault.jpg10.0 KiB7.4 KiB
Calabrio: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/calabrio.png8.3 KiB7.4 KiB
Scarf: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/scarf.png5.7 KiB5.1 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-22-DIV
nodeLabel: Try it! Type Haskell expressions in here. λ    Got 5 minutes? Type help to sta…
path: 1,HTML,2,BODY,1,DIV,11,DIV
selector: body.page-home > div.wrap > div.pattern-bg
snippet: <div class="pattern-bg">

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
www.haskell.org/css/hl.css17.0 KiB240 ms
www.haskell.org/css/fonts.css410 B
cdn.jsdelivr.net/npm/glider-js@1/glider.min.js3.2 KiB150 ms
cdn.jsdelivr.net/npm/glider-js@1/glider.min.css1.1 KiB751 ms

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

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.

ElementLayout shift score
(click to insert) div#guide > div.indent > p > small.note
0.120
Why Haskell? A new paradigm Express your ideas clearly and learn a new way of … body.page-home > div.wrap > div.features
0.077

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: 0.0 ms 4.1 KiB
URLTransfer SizeEst Savings
www.haskell.org/js/jquery.console.js7.0 KiB4.1 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: 0.0 ms 15.2 KiB
URLTransfer SizeEst Savings
www.haskell.org/css/hl.css16.8 KiB15.2 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
Calabrio: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/calabrio.png
HubSpot: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/hubspot.png
Bitnomial: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/bitnomial.png
Serokell: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/serokell.png
finn.no: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/finn.png
Scarf: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/scarf.png
NoRedInk: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/noredink.png
CentralApp: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/centralapp.png
IOHK: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/iohk.png
Hasura: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/hasura.png
Fission: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/fission.png
e-bot7: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/e-bot7.png
Stack Builders: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/stackbuilders.png
Foxhound Systems: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/foxhoundsystems.png
Mercury: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/mercury.png
Imagine AI: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/imagineai.png
Scrive: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/Scrive.png
Bellroy: Logo div.span3 > div.thumbnail > a > img.img
www.haskell.org/testimonials/logos/bellroy.png
div.row > div.span3 > a.thumbnail > img.img-responsive div.row > div.span3 > a.thumbnail > img.img-responsive
i1.ytimg.com/vi/re96UgMk6GQ/mqdefault.jpg
div.row > div.span3 > a.thumbnail > img.img-responsive div.row > div.span3 > a.thumbnail > img.img-responsive
i1.ytimg.com/vi/LnX3B9oaKzw/mqdefault.jpg
div.row > div.span3 > a.thumbnail > img.img-responsive div.row > div.span3 > a.thumbnail > img.img-responsive
i1.ytimg.com/vi/4RuLzL_q0zs/mqdefault.jpg
div.row > div.span3 > a.thumbnail > img.img-responsive div.row > div.span3 > a.thumbnail > img.img-responsive
i1.ytimg.com/vi/t1e8gqXLbsU/mqdefault.jpg
div.row > div.span3 > a.thumbnail > img.img-responsive div.row > div.span3 > a.thumbnail > img.img-responsive
i1.ytimg.com/vi/WHVMjMIJnB4/mqdefault.jpg
Haskell div.row > div.span6 > div.branding > img.img-responsive
www.haskell.org/img/haskell-logo.svg
div.row > div.span3 > a.thumbnail > img.img-responsive div.row > div.span3 > a.thumbnail > img.img-responsive
i1.ytimg.com/vi/IzQTfh-Iuds/mqdefault.jpg

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

●Max Potential First Input Delay 110 ms
●Document request latency
●Optimize DOM size
●Font display
●LCP breakdown
●Modern HTTP
●Optimize viewport for mobile
●Minify CSS
●Reduce unused JavaScript
●Avoids enormous network payloads Total size was 858 KiB
●JavaScript execution time 0.2 s
●Minimizes main-thread work 1.1 s
●Avoid long main-thread tasks 4 long tasks found
●Page didn't prevent back/forward cache restoration
●Network Requests
●Network Round Trip Times 90 ms
●Server Backend Latencies 150 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 180 ms
○INP breakdown
○User Timing marks and measures
○Avoid non-composited animations
83

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
nav.navbar > div.container > div.navbar-header > button.navbar-toggle nav.navbar > div.container > div.navbar-header > button.navbar-toggle

Labels ensure that form controls are announced properly by assistive technologies, like screen readers. Learn more about form element labels.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.span6 > div#console > div.jquery-console-inner > textarea.jquery-console-typer div.span6 > div#console > div.jquery-console-inner > textarea.jquery-console-typer

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.

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
primes div.branding > div.code-sample > pre > span.hs-definition

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
Escape from the ivory tower: The Haskell journey, by Simon Peyton-Jones div.span3 > a.thumbnail > div.caption > h5
Calabrio div.thumbnail > div.testimonial-caption > a > h4

These are opportunities to improve keyboard navigation in your application.

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]`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 have valid values
●`[aria-*]` attributes are valid and not misspelled
●Image elements have `[alt]` attributes
●`[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 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.
●Links have a discernible name
●Touch targets have sufficient size and spacing.
●Deprecated ARIA roles were not used
●Identical links have the same purpose.
●Elements with visible text labels have matching accessible names.
○`[accesskey]` values are unique
○`button`, `link`, and `menuitem` elements have accessible names
○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.
○`[aria-hidden="true"]` elements do not contain focusable descendents
○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
○Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
○List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements
○The document does not use `<meta http-equiv="refresh">`
○`<object>` elements have alternate text
○Select elements have associated label elements.
○Skip links are focusable.
○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.
○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.
96

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.

SourceDescription
i1.ytimg.com/vi/IzQTfh-Iuds/mqdefault.jpg
Failed to load resource: the server responded with a status of 404 ()
●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
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`

Send Feedback