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
www.legislation.gov.uk/images/uk-govt-crest.png	0.0 ms	232.6 KiB
www.legislation.gov.uk/scripts/jquery-3.7.1.min.js	0.0 ms	30.3 KiB
www.legislation.gov.uk/styles/website.css	0.0 ms	30.0 KiB
www.legislation.gov.uk/styles/screen.css	0.0 ms	20.5 KiB
www.legislation.gov.uk/images/chrome/homepageCountryBG/welcome.png	0.0 ms	18.8 KiB
www.legislation.gov.uk/scripts/chrome.js	0.0 ms	16.7 KiB
www.legislation.gov.uk/images/ogl.png	0.0 ms	9.0 KiB
www.legislation.gov.uk/images/chrome/site_logo_legislation.gif	0.0 ms	7.3 KiB
www.legislation.gov.uk/images/chrome/nat-archive-delivered-en.svg	0.0 ms	5.2 KiB
www.legislation.gov.uk/scripts/cookie-directive.js	0.0 ms	4.3 KiB
www.legislation.gov.uk/scripts/CentralConfig.js	0.0 ms	4.2 KiB
www.legislation.gov.uk/scripts/homepageChrome.js	0.0 ms	2.1 KiB
/scripts/jquery-cookie-directive/jquery-cookie-functions.js	0.0 ms	1.8 KiB
www.legislation.gov.uk/scripts/survey/survey.js	0.0 ms	1.8 KiB
www.legislation.gov.uk/scripts/jquery-cookie-directive/jquery.cookie.js	0.0 ms	1.7 KiB
www.legislation.gov.uk/images/chrome/ogl-symbol.gif	0.0 ms	1.6 KiB
www.legislation.gov.uk/images/chrome/settings-sharp.svg	0.0 ms	1.6 KiB
www.legislation.gov.uk/styles/buy-now.css	0.0 ms	1.4 KiB
www.legislation.gov.uk/styles/survey/survey.css	0.0 ms	1.2 KiB
www.legislation.gov.uk/images/chrome/pause-circle-outline.svg	0.0 ms	1.2 KiB
www.legislation.gov.uk/styles/print.css	0.0 ms	1.1 KiB
www.legislation.gov.uk/images/chrome/close-sharp-inverse.svg	0.0 ms	923 B
www.legislation.gov.uk/images/chrome/checkmark-sharp.svg	0.0 ms	881 B
www.legislation.gov.uk/images/analytics/cookiesBannerIgnored.gif	0.0 ms	638 B

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.

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-div

nodeLabel: Welcome

path: 1,html,1,body,3,div,3,div,1,div,1,div,0,div

selector: div#layout2 > div#intro > div#animContent > div.welcome

snippet: <div xmlns="http://www.w3.org/1999/xhtml" class="welcome" style="display: block;">

HTTP/2 and HTTP/3 offer many benefits over HTTP/1.1, such as multiplexing. Learn more about using modern HTTP.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Protocol
www.legislation.gov.uk/	http/1.1
www.legislation.gov.uk/styles/screen.css	http/1.1
www.legislation.gov.uk/styles/survey/survey.css	http/1.1
www.legislation.gov.uk/scripts/jquery-3.7.1.min.js	http/1.1
www.legislation.gov.uk/scripts/CentralConfig.js	http/1.1
www.legislation.gov.uk/scripts/survey/survey.js	http/1.1
www.legislation.gov.uk/scripts/chrome.js	http/1.1
www.legislation.gov.uk/scripts/homepageChrome.js	http/1.1
www.legislation.gov.uk/styles/website.css	http/1.1
www.legislation.gov.uk/styles/print.css	http/1.1
www.legislation.gov.uk/styles/buy-now.css	http/1.1
www.legislation.gov.uk/scripts/jquery-cookie-directive/jquery.cookie.js	http/1.1
/scripts/jquery-cookie-directive/jquery-cookie-functions.js	http/1.1
www.legislation.gov.uk/scripts/cookie-directive.js	http/1.1
www.legislation.gov.uk/images/chrome/site_logo_legislation.gif	http/1.1
www.legislation.gov.uk/images/chrome/ogl-symbol.gif	http/1.1
www.legislation.gov.uk/images/uk-govt-crest.png	http/1.1
www.legislation.gov.uk/images/chrome/nat-archive-delivered-en.svg	http/1.1
www.legislation.gov.uk/images/chrome/homepageCountryBG/welcome.png	http/1.1
www.legislation.gov.uk/images/ogl.png	http/1.1
www.legislation.gov.uk/images/analytics/cookiesBannerIgnored.gif	http/1.1
www.legislation.gov.uk/images/chrome/checkmark-sharp.svg	http/1.1
www.legislation.gov.uk/images/chrome/settings-sharp.svg	http/1.1
www.legislation.gov.uk/images/chrome/close-sharp-inverse.svg	http/1.1
www.legislation.gov.uk/images/chrome/pause-circle-outline.svg	http/1.1
www.legislation.gov.uk/favicon.ico	http/1.1

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
/css2?family=Roboto:ital,wght@0,100;0,200;0,300;0,400;0,5...	3.0 KiB	820 ms
www.legislation.gov.uk/scripts/cookie-directive.js	4.3 KiB	336 ms
www.legislation.gov.uk/styles/buy-now.css	1.4 KiB	502 ms
www.legislation.gov.uk/scripts/jquery-3.7.1.min.js	30.3 KiB	1.2 s
www.legislation.gov.uk/styles/website.css	30.0 KiB	1.2 s
www.legislation.gov.uk/styles/screen.css	20.5 KiB	835 ms
www.legislation.gov.uk/scripts/chrome.js	16.7 KiB	336 ms
www.legislation.gov.uk/scripts/survey/survey.js	1.8 KiB	170 ms
www.legislation.gov.uk/scripts/CentralConfig.js	4.2 KiB	170 ms
www.legislation.gov.uk/scripts/homepageChrome.js	2.1 KiB	170 ms
/scripts/jquery-cookie-directive/jquery-cookie-functions.js	1.8 KiB	170 ms
www.legislation.gov.uk/scripts/jquery-cookie-directive/jquery.cookie.js	1.7 KiB	502 ms
www.legislation.gov.uk/styles/survey/survey.css	1.2 KiB	502 ms

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.


html > head > meta `html > head > meta`

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: 827 ms

URL	Time Spent
legislation.gov.uk/	827 ms
www.legislation.gov.uk/	0.0 ms

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

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: 500 ms 40.4 KiB

URL	Transfer Size	Est Savings
www.legislation.gov.uk/styles/website.css	29.4 KiB	23.4 KiB
www.legislation.gov.uk/styles/screen.css	19.9 KiB	17.1 KiB

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 0.0 ms 8.7 KiB

URL	Transfer Size	Est Savings
www.legislation.gov.uk/styles/screen.css	20.5 KiB	4.9 KiB
www.legislation.gov.uk/styles/website.css	30.0 KiB	3.8 KiB

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 9.2 KiB

URL	Transfer Size	Est Savings
www.legislation.gov.uk/scripts/chrome.js	16.1 KiB	9.2 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
legislation.gov.uk homepage call-to-action widget `div#intro > div#homeCTA > div.content > img`	www.legislation.gov.uk/images/chrome/site_logo_legislation.gif
html > body#per > img `html > body#per > img`	www.legislation.gov.uk/images/analytics/cookiesBannerIgnored.gif

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

●Layout shift culprits

●Optimize DOM size

●Font display

●Forced reflow

●Improve image delivery

●LCP breakdown

●Max Potential First Input Delay 20 ms

●Reduce unused JavaScript

●Avoids enormous network payloads Total size was 444 KiB

●JavaScript execution time 0.1 s

●Minimizes main-thread work 0.8 s

●Avoid long main-thread tasks 1 long task found

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 30 ms

●Server Backend Latencies 20 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Initial server response time was short Root document took 400 ms

●Avoid large layout shifts 1 layout shift found

○INP breakdown

○User Timing marks and measures

○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.

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

●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.

●Select elements have associated label elements.

●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 are distinguishable without relying on color.

●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

●Touch targets have sufficient size and spacing.

●`[lang]` attributes have a valid value

●Heading elements appear in a sequentially-descending order

●Skip links are focusable.

●Identical links have the same purpose.

○`[accesskey]` values are unique

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

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

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

○Deprecated ARIA roles were not used

○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 use only permitted ARIA attributes

○`[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

○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

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

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

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

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

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

○ARIA IDs are unique

○No form fields have multiple labels

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

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

○Input buttons have discernible text.

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

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

○`<object>` elements have alternate text

○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.

○`<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.

○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.

100

Best Practices

●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 browser errors logged to the console

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

●Ensure CSP is effective against XSS attacks

●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

○Use a strong HSTS policy

○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.

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
Welcome `div#intro > ul#countryLeg > li > a#welcome`
United Kingdom `div#intro > ul#countryLeg > li > a#uk`
Scotland `div#intro > ul#countryLeg > li > a#scotland`
Wales `div#intro > ul#countryLeg > li > a#wales`
Northern Ireland `div#intro > ul#countryLeg > li > a#ni`
Legislation originating from the EU `div#intro > ul#countryLeg > li > a#eu`

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

●Links have descriptive text

●robots.txt is valid

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

○Document has a valid `rel=canonical`