Lighthouse Desktop

· 0 checks — Desktop 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.

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-IMG

nodeLabel: A Cancer Research UK researcher in a lab looking at a device in her hand. She's…

path: 2,HTML,1,BODY,2,DIV,0,DIV,0,DIV,0,DIV,0,IMG

selector: div.css-1xpbriy > div.chakra-container > div.css-3gj8s1 > img

snippet: <img alt="A Cancer Research UK researcher in a lab looking at a device in her hand. …" decoding="async" data-nimg="fill" style="position: absolute; height: 100%; width: 100%; inset: 0px;" sizes="100vw" srcset="/_next/image?url=https%3A%2F%2Fimages.ctfassets.net%2Fu7vsjnoopqo5%2F4KvYf…" src="https://www.cancerresearchuk.org/_next/image?url=https%3A%2F%2Fimages.ctfa…">

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

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
A photo of Cancer Research UK fundraisers getting ready for a food sale. `a.chakra-card > div.card-imagery-container > div.chakra-aspect-ratio > img.css-4hbfir`	/_next/image?url=https%3A%2F%2Fdownloads.ctfassets.net%2F...	50.4 KiB	29.5 KiB
A Cancer Research UK researcher in a lab looking at a device in her hand. She's… `div.css-1xpbriy > div.chakra-container > div.css-3gj8s1 > img`	/_next/image?url=https%3A%2F%2Fimages.ctfassets.net%2Fu7v...	66.1 KiB	27.3 KiB
A photo of a Cancer Research UK volunteer showing the way to a runner. `a.chakra-card > div.card-imagery-container > div.chakra-aspect-ratio > img.css-4hbfir`	/_next/image?url=https%3A%2F%2Fimages.ctfassets.net%2Fu7v...	43.7 KiB	22.8 KiB

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
www.cancerresearchuk.org/_next/static/css/c682fa5ca7232dbe.css	3.4 KiB
www.cancerresearchuk.org/_next/static/css/761dc5ff23fcdfa0.css	3.9 KiB
www.cancerresearchuk.org/_next/static/css/c361d1f26b524758.css	3.6 KiB

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: 276 ms

URL	Time Spent
cancerresearchuk.org/	276 ms
www.cancerresearchuk.org/	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 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: 80 ms 567.6 KiB

URL	Transfer Size	Est Savings
www.googletagmanager.com/gtm.js?id=GTM-KHMJ7CS	181.1 KiB	78.0 KiB
www.cancerresearchuk.org/_next/static/chunks/7180-be8f246206a70c65.js	170.6 KiB	77.5 KiB
www.googletagmanager.com/gtag/js?id=G-58736Z2GNN&cx=c&gtm=4e64h1	168.3 KiB	76.9 KiB
www.googletagmanager.com/gtag/js?id=AW-986083629&cx=c&gtm=4e64h1	137.2 KiB	65.7 KiB
www.googletagmanager.com/gtag/js?id=DC-8727222&cx=c&gtm=4e64h1	130.1 KiB	64.1 KiB
www.cancerresearchuk.org/_next/static/chunks/2691-38189575cf339bed.js	60.5 KiB	48.8 KiB
www.cancerresearchuk.org/_next/static/chunks/7105-e8c503187482c546.js	259.4 KiB	46.3 KiB
www.cancerresearchuk.org/_next/static/chunks/1377-c76d500bf8de9995.js	252.7 KiB	41.6 KiB
www.cancerresearchuk.org/_next/static/chunks/7693-ddc473c47d5fbf1c.js	51.7 KiB	37.3 KiB
www.cancerresearchuk.org/_next/static/chunks/4052-cc3a4da56124ab29.js	39.4 KiB	31.3 KiB

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size
www.cancerresearchuk.org/_next/static/chunks/7105-e8c503187482c546.js	262.6 KiB
www.cancerresearchuk.org/_next/static/chunks/1377-c76d500bf8de9995.js	256.0 KiB
www.googletagmanager.com/gtm.js?id=GTM-KHMJ7CS	181.5 KiB
www.cancerresearchuk.org/_next/static/chunks/7180-be8f246206a70c65.js	174.1 KiB
www.googletagmanager.com/gtag/js?id=G-58736Z2GNN&cx=c&gtm=4e64h1	168.3 KiB
www.cancerresearchuk.org/_next/static/media/fb98212e27cc7064-s.p.woff	166.0 KiB
www.cancerresearchuk.org/_next/static/media/22f59f5d5b479322-s.p.woff	143.8 KiB
www.googletagmanager.com/gtag/js?id=AW-986083629&cx=c&gtm=4e64h1	137.3 KiB
www.googletagmanager.com/gtag/js?id=DC-8727222&cx=c&gtm=4e64h1	130.1 KiB
www.cancerresearchuk.org/_next/static/media/e21fa8781a9a32b3-s.p.woff	74.9 KiB

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

●Max Potential First Input Delay 100 ms

●Use efficient cache lifetimes

●Layout shift culprits

●Optimize DOM size

●Font display

●Forced reflow

●LCP breakdown

●Modern HTTP

●Optimize viewport for mobile

●Minify CSS

●Minify JavaScript

●Reduce unused CSS

●User Timing marks and measures 1 user timing

●JavaScript execution time 0.5 s

●Minimizes main-thread work 0.8 s

●Avoid long main-thread tasks 3 long tasks found

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

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 50 ms

●Server Backend Latencies 30 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Initial server response time was short Root document took 0 ms

○INP breakdown

○Avoid non-composited animations

○Avoid large layout shifts

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

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
ul.chakra-stack > li.css-8atqhb > label.css-8atqhb > input#radio-_R_9l6dbahmledbqunb_ `ul.chakra-stack > li.css-8atqhb > label.css-8atqhb > input#radio-_R_9l6dbahmledbqunb_`
ul.chakra-stack > li.css-8atqhb > label.css-8atqhb > input#radio-_R_al6dbahmledbqunb_ `ul.chakra-stack > li.css-8atqhb > label.css-8atqhb > input#radio-_R_al6dbahmledbqunb_`
ul.chakra-stack > li.css-8atqhb > label.css-8atqhb > input#radio-_R_bl6dbahmledbqunb_ `ul.chakra-stack > li.css-8atqhb > label.css-8atqhb > input#radio-_R_bl6dbahmledbqunb_`

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.

Visible text labels that do not match the accessible name can result in a confusing experience for screen reader users. Learn more about accessible names.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Donate now `div.chakra-tabs__tab-panels > div#tabs-_R_1ahmledbqunb_--tabpanel-0 > div.chakra-form-control > button.chakra-button`

○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

●Buttons have an accessible name

●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

●`[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

●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

●Deprecated ARIA roles were not used

○`[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 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

○Links are distinguishable without relying on color.

○Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).

○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.

○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.

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.

Source	Description
www.cancerresearchuk.org/_next/static/chunks/app/layout-f0fd3adaeb422483.js	`One Trust error [object Event]`

Source maps translate minified code to the original source code. This helps developers debug in production. In addition, Lighthouse is able to provide further insights. Consider deploying source maps to take advantage of these benefits. Learn more about source maps.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL
www.cancerresearchuk.org/_next/static/chunks/7180-be8f246206a70c65.js
www.cancerresearchuk.org/_next/static/chunks/7105-e8c503187482c546.js
www.cancerresearchuk.org/_next/static/chunks/1377-c76d500bf8de9995.js

●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

●Ensure proper origin isolation with COOP

●Mitigate DOM-based XSS with Trusted Types

○Redirects HTTP traffic to HTTPS

○Use a strong HSTS policy

○Mitigate clickjacking with XFO or CSP

○Detected JavaScript libraries

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`