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.

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Why this matters

Performance issues directly impact user engagement and conversion rates.

description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.

title: Preconnected origins

value: no origins were preconnected

description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.

title: Preconnect candidates

value: No additional origins are good candidates for preconnecting

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size	Duration
cookiemanager.parliament.uk/cookie-manager-v2.css	1.6 KiB	779 ms
publications.parliament.uk/styles/global.css	7.0 KiB

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
/cdn-cgi/challenge-platform/h/b/scripts/jsd/0b8fb825cb67/...	14400.0 s	12.1 KiB
publications.parliament.uk/pa/img/icon_business.jpg	30.0 s	7.4 KiB
publications.parliament.uk/pa/img/icon_records_and_publications.jpg	30.0 s	7.4 KiB
publications.parliament.uk/pa/img/icon_members_and_staff.jpg	30.0 s	7.2 KiB
publications.parliament.uk/pa/img/icon_about_parliament.jpg	30.0 s	7.0 KiB
publications.parliament.uk/styles/global.css	30.0 s	7.0 KiB
publications.parliament.uk/server-side/images/parliament_logo.gif	30.0 s	6.2 KiB
cookiemanager.parliament.uk/cookie-manager-v2.js	14400.0 s	4.0 KiB
publications.parliament.uk/styles/global_print.css	30.0 s	2.7 KiB
publications.parliament.uk/pa/img/icon_house_of_commons.png	30.0 s	2.1 KiB
publications.parliament.uk/pa/img/icon_house_of_lords.png	30.0 s	2.0 KiB
publications.parliament.uk/pa/img/icon_parliament_live.png	30.0 s	1.5 KiB
cookiemanager.parliament.uk/cookie-manager-v2.css	14400.0 s	1.6 KiB
publications.parliament.uk/images/global/topnavborder.gif	30.0 s	539 B

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
Business icon `tbody > tr > td > img`	publications.parliament.uk/pa/img/icon_business.jpg	7.4 KiB	7.2 KiB
Publications icon `tbody > tr > td > img`	publications.parliament.uk/pa/img/icon_records_and_publications.jpg	7.4 KiB	7.2 KiB
People icon `tbody > tr > td > img`	publications.parliament.uk/pa/img/icon_members_and_staff.jpg	7.1 KiB	7.0 KiB
About Parliament icon `tbody > tr > td > img`	publications.parliament.uk/pa/img/icon_about_parliament.jpg	6.9 KiB	6.8 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.

●Max Potential First Input Delay 100 ms

●Layout shift culprits

●Document request latency

●Optimize DOM size

●Font display

●Forced reflow

●LCP breakdown

●Modern HTTP

●Time to Interactive 1.7 s

●Minify CSS

●Minify JavaScript

●Reduce unused CSS

●Reduce unused JavaScript

●Avoids enormous network payloads Total size was 74 KiB

●JavaScript execution time 0.2 s

●Minimizes main-thread work 0.5 s

●Avoid long main-thread tasks 1 long task found

●Image elements have explicit `width` and `height`

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 20 ms

●Server Backend Latencies 50 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 90 ms

●Avoid large layout shifts 1 layout shift found

○INP breakdown

○LCP request discovery

○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.

Internationalization and localization

If a page doesn't specify a `lang` attribute, a screen reader assumes that the page is in the default language that the user chose when setting up the screen reader. If the page isn't actually in the default language, then the screen reader might not announce the page's text correctly. Learn more about the `lang` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
html `html`

These are opportunities to improve the interpretation of your content by users in different locales.

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#banner > div#banner_top > div#banner_img > a `div#banner > div#banner_top > div#banner_img > a`

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.

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.

Screen readers have features to make navigating tables easier. Ensuring that `<td>` elements in a large table (3 or more cells in width and height) have an associated table header may improve the experience for screen reader users. Learn more about table headers.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
About Parliament includes sections on About MPs, Lords & officers, Living Heri… `body > div#contentHolder > table`

○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

●Background and foreground colors have a sufficient contrast ratio

●Document has a `<title>` element

●Links are distinguishable without relying on color.

●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.

●Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.

●Heading elements appear in a sequentially-descending order

●Identical links have the same purpose.

●Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.

○`[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 a valid value for its `[lang]` attribute

○`<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

○Form elements have associated labels

○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.

○Skip links are focusable.

○No element has a `[tabindex]` value greater than 0

○`<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.

○Elements with visible text labels have matching accessible names.

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.

	URL	Displayed size	Actual size	Expected size
div#banner_top > div#banner_img > a > img `div#banner_top > div#banner_img > a > img`	publications.parliament.uk/server-side/images/parliament_logo.gif	280 x 45	280 x 45	420 x 68
House of Commons icon `tbody > tr > td > img`	publications.parliament.uk/pa/img/icon_house_of_commons.png	35 x 35	35 x 35	53 x 53
House of Lords icon `tbody > tr > td > img`	publications.parliament.uk/pa/img/icon_house_of_lords.png	35 x 35	35 x 35	53 x 53
Video and Audio Live icon `tbody > tr > td > img`	publications.parliament.uk/pa/img/icon_parliament_live.png	35 x 35	35 x 35	53 x 53
People icon `tbody > tr > td > img`	publications.parliament.uk/pa/img/icon_members_and_staff.jpg	30 x 30	30 x 30	45 x 45
Publications icon `tbody > tr > td > img`	publications.parliament.uk/pa/img/icon_records_and_publications.jpg	30 x 30	30 x 30	45 x 45
About Parliament icon `tbody > tr > td > img`	publications.parliament.uk/pa/img/icon_about_parliament.jpg	30 x 29	30 x 29	45 x 44
Business icon `tbody > tr > td > img`	publications.parliament.uk/pa/img/icon_business.jpg	30 x 29	30 x 29	45 x 44

Browser Compatibility

Specifying a doctype prevents the browser from switching to quirks-mode. Learn more about the doctype declaration.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A character encoding declaration is required. It can be done with a `<meta>` tag in the first 1024 bytes of the HTML or in the Content-Type HTTP response header. Learn more about declaring the character encoding.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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
SharedStorage	publications.parliament.uk/cdn-cgi/challenge-platform/scripts/jsd/main.js
StorageType.persistent is deprecated. Please use standardized navigator.storage instead.	publications.parliament.uk/cdn-cgi/challenge-platform/scripts/jsd/main.js
Fledge	publications.parliament.uk/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

●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

●Page has valid source maps

○Redirects HTTP traffic to HTTPS

○Mitigate clickjacking with XFO or CSP

○Detected JavaScript libraries

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

Meta descriptions may be included in search results to concisely summarize page content. Learn more about the meta description.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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

●Page has successful HTTP status code

●Links have descriptive text

●Links are crawlable

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

○robots.txt is valid

○Document has a valid `rel=canonical`