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
/pagead/managed/js/activeview/current/ufs_web_display.js	3600.0 s	73.1 KiB
cdn.cookielaw.org/scripttemplates/202505.2.0/otBannerSdk.js	86400.0 s	119.2 KiB
/do/10.1016/4f9d9162-93c9-4d6f-ac08-283f4e73cd6d/single_c...	86400.0 s	99.8 KiB
/do/10.1016/a7d423f9-578d-40e1-89a3-8addecd9517e/single_c...	86400.0 s	90.8 KiB
/products/marlin/lancet/releasedAssets/fonts/NexusSansWeb...	86400.0 s	78.8 KiB
/products/marlin/lancet/releasedAssets/fonts/NexusSansWeb...	86400.0 s	74.2 KiB
/products/marlin/lancet/releasedAssets/fonts/NexusSansWeb...	86400.0 s	70.4 KiB
/pb-assets/Lancet/homepage/latest_news/latest-news-260411...	86400.0 s	62.4 KiB
/products/marlin/lancet/releasedAssets/fonts/NexusSansOff...	86400.0 s	60.5 KiB
/products/marlin/lancet/releasedAssets/fonts/NexusSansOff...	86400.0 s	57.7 KiB
/pb-assets/Lancet/homepage/latest_news/latest-news-260411...	86400.0 s	57.1 KiB
/do/10.1016/04f8c4ae-ce4a-414f-9e8c-da80cc73d001/single_c...	86400.0 s	56.2 KiB
/products/marlin/lancet/releasedAssets/fonts/NexusSansOff...	86400.0 s	56.1 KiB
/do/10.1016/2e3f8d55-c132-448b-8470-b6492f45d646/single_c...	86400.0 s	55.5 KiB
/products/marlin/lancet/releasedAssets/js/main.bundle-582...	604800.0 s	218.0 KiB
/pb-assets/Lancet/homepage/latest_news/latest-news-260411...	86400.0 s	43.7 KiB
/products/marlin/lancet/releasedAssets/fonts/icomoon/font...	86400.0 s	41.9 KiB
/products/marlin/lancet/releasedAssets/fonts/icomoon-d4d1...	86400.0 s	31.9 KiB
/products/marlin/lancet/releasedAssets/css/build-02c4f504...	604800.0 s	104.9 KiB
/cdn-cgi/challenge-platform/h/b/scripts/jsd/0b8fb825cb67/...	14400.0 s	13.0 KiB
/pb-assets/Lancet/homepage/latest_news/latest-news-260411...	86400.0 s	20.0 KiB
cdn.cookielaw.org/logos/static/ot_company_logo.png	86400.0 s	19.1 KiB
/products/marlin/lancet/releasedAssets/js/selected.bundle...	604800.0 s	54.1 KiB
/products/marlin/lancet/releasedAssets/css/selected-02c4f...	604800.0 s	51.3 KiB
static.cloudflareinsights.com/beacon.min.js	86400.0 s	10.7 KiB
cdn.cookielaw.org/scripttemplates/otSDKStub.js	86400.0 s	9.1 KiB
/beacon.min.js/vcd15cbe7772f49c399c6a5babf22c124171768917...	86400.0 s	6.9 KiB
/products/marlin/lancet/releasedAssets/fonts/elsevierword...	86400.0 s	4.9 KiB
/products/marlin/lancet/releasedAssets/fonts/elsevierword...	86400.0 s	4.6 KiB
rum-static.pingdom.net/prum.min.js	43200.0 s	2.8 KiB
cdn.cookielaw.org/logos/static/powered_by_logo.svg	86400.0 s	2.7 KiB
/products/marlin/lancet/releasedAssets/js/lazy-imports-35...	604800.0 s	9.9 KiB
www.thelancet.com/pb-assets/ux3/logos/lancet/LANCET-1665147351037.svg	86400.0 s	2.3 KiB
/products/marlin/lancet/releasedAssets/js/search-31ba933e...	604800.0 s	8.2 KiB
pagead2.googlesyndication.com/pagead/js/r20260420/r20110914/abg_lite_fy2021.js	1209600.0 s	8.4 KiB
www.thelancet.com/pb/assets/raw/Lancet/images/relx3-1559736305887.png	86400.0 s	2.0 KiB
/products/marlin/lancet/releasedAssets/js/vendors~lazy-im...	604800.0 s	7.4 KiB
/1/16e2192192?a=916937540&sa=1&v=1177.96a4d39&t=Unnamed%2...	0.0 ms	693 B
/pb-assets/Lancet/test/icons/gizmo-navigate-right-white-1...	86400.0 s	1.6 KiB
www.thelancet.com/templates/jsp/_style2/_marlin/images/bg_adHoriz.gif	0.0 ms	608 B
/pb-assets/Lancet/test/icons/gizmo-navigate-right-white-1...	86400.0 s	1.1 KiB
/products/marlin/lancet/releasedAssets/js/dynamic-imports...	604800.0 s	3.7 KiB
/products/marlin/lancet/releasedAssets/js/megaMenu-c0b9d6...	604800.0 s	3.7 KiB
/products/marlin/lancet/releasedAssets/js/plumX-f978978bf...	604800.0 s	3.3 KiB
www.thelancet.com/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js	172800.0 s	850 B
/products/marlin/lancet/releasedAssets/js/profile-a663aac...	604800.0 s	1.6 KiB
/pagead/js/r20260420/r20110914/client/window_focus_fy2021.js	1209600.0 s	1.2 KiB
/products/marlin/lancet/releasedAssets/css/print-02c4f504...	604800.0 s	735 B
/products/marlin/lancet/releasedAssets/js/requestidlecall...	604800.0 s	552 B
/beacon.min.js/vcd15cbe7772f49c399c6a5babf22c124171768917...	86400.0 s	0 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.

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Est Savings
www.thelancet.com/pb-assets/Lancet/homepage/carousel/fonts/2D333F_2_0.woff	210 ms
www.thelancet.com/pb-assets/Lancet/homepage/carousel/fonts/2D333F_1_0.woff2	200 ms
www.thelancet.com/pb-assets/Lancet/homepage/carousel/fonts/2D333F_1_0.woff	200 ms
www.thelancet.com/pb-assets/Lancet/homepage/carousel/fonts/2D333F_2_0.woff2	170 ms
/products/marlin/lancet/releasedAssets/fonts/icomoon-d4d1...	30 ms
/products/marlin/lancet/releasedAssets/fonts/source-sans-...	20 ms
/s/sourcesanspro/v23/6xK3dSBYKcSV-LCoeQqfX1RYOo3qOK7lujVj...	5.0 ms

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
Children stacking their hands on top of one another on a grassy field. Copyrigh… `div.highlights-img-inner > span > a > img`	/pb-assets/Lancet/homepage/latest_news/latest-news-260411...	61.6 KiB	53.0 KiB
Fishermen unload mangrove seedlings that they will plant along a coastal area a… `div.highlights-img-inner > span > a > img`	/pb-assets/Lancet/homepage/latest_news/latest-news-260411...	56.4 KiB	47.8 KiB
The Lancet Summit: shaping the future of diabetes prevention. Image credit: Ixe… `body.jar > div#google_image_div > a#aw0 > img.img_ad`	tpc.googlesyndication.com/simgad/11323284346351336585	44.9 KiB	42.5 KiB
A medical professional is holding a smear test kit for HPV. Copyright: Peter Da… `div.highlights-img-inner > span > a > img`	/pb-assets/Lancet/homepage/latest_news/latest-news-260411...	43.0 KiB	34.4 KiB
A logo for The Lancet Pulse podcast which features a blue background and white … `div.highlights-img-inner > span > a > img`	/pb-assets/Lancet/homepage/latest_news/latest-news-260411...	19.3 KiB	10.7 KiB

Each subpart has specific improvement strategies. Ideally, most of the LCP time should be spent on loading the resources, not within delays.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:label label:Subpart valueType:text] map[key:duration label:Duration valueType:ms]]

items: [map[duration:1338.069 label:Time to first byte subpart:timeToFirstByte] map[duration:2290.66 label:Element render delay subpart:elementRenderDelay]]

lhId: page-4-DIV

nodeLabel: We use cookies that are necessary to make our site work. We may also use additi…

path: 1,HTML,1,BODY,11,DIV,1,DIV,0,DIV,0,DIV,0,DIV,0,DIV,1,DIV,0,DIV

selector: div.ot-sdk-row > div#onetrust-group-container > div#onetrust-policy > div#onetrust-policy-text

snippet: <div id="onetrust-policy-text">

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

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
/wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~selected-le...	68.3 KiB	1.4 s
/wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~selected-le...	4.1 KiB	182 ms
www.thelancet.com/wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~product.css	13.4 KiB	634 ms
cdn.cookielaw.org/scripttemplates/otSDKStub.js	9.1 KiB	1.1 s
fonts.googleapis.com/css?family=Open+Sans	2.0 KiB	765 ms
www.thelancet.com/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js	850 B	483 ms

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: 2.3 s

URL	Time Spent
thelancet.com/	935 ms
/as/authorization.oauth2?platSite=LT%2Fthelancet&response...	866 ms
/callback?red_uri=%2F&code=V3QOlhBAVO6PUAsqIxwlhWnP-pPwhl...	499 ms
www.thelancet.com/	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

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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: 70 ms 16.4 KiB

URL	Transfer Size	Est Savings
www.thelancet.com/pb-assets/Lancet/homepage/carousel/js/flickity.pkgd.js	25.8 KiB	9.9 KiB
inline: function gpt_CheckEnvironment() { …	11.5 KiB	6.4 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: 820 ms 135.5 KiB

URL	Transfer Size	Est Savings
/products/marlin/lancet/releasedAssets/css/build-02c4f504...	104.6 KiB	100.6 KiB
	25.3 KiB	22.0 KiB
www.thelancet.com/wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~product.css	13.1 KiB	12.9 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: 2.6 s 453.0 KiB

URL	Transfer Size	Est Savings
/products/marlin/lancet/releasedAssets/js/main.bundle-582...	217.7 KiB	149.2 KiB
/pagead/managed/js/gpt/m202604090102/pubads_impl.js?cb=31...	187.6 KiB	101.0 KiB
cdn.cookielaw.org/scripttemplates/202505.2.0/otBannerSdk.js	119.0 KiB	62.1 KiB
www.googletagmanager.com/gtag/js?id=AW-800477382	140.7 KiB	58.1 KiB
/wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~selected-le...	68.0 KiB	51.5 KiB
/pagead/managed/js/activeview/current/ufs_web_display.js	73.1 KiB	31.1 KiB

Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to reduce Javascript execution time.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Total CPU Time	Script Evaluation	Script Parse
www.thelancet.com/	4.0 s	1.3 s	61 ms
Unattributable	1.4 s	241 ms	0.0 ms
/pagead/managed/js/gpt/m202604090102/pubads_impl.js?cb=31...	1.1 s	848 ms	147 ms
/products/marlin/lancet/releasedAssets/js/main.bundle-582...	1.0 s	604 ms	149 ms
/pagead/managed/js/activeview/current/ufs_web_display.js	584 ms	463 ms	45 ms
cdn.cookielaw.org/scripttemplates/202505.2.0/otBannerSdk.js	479 ms	324 ms	83 ms
www.googletagmanager.com/gtag/js?id=AW-800477382	454 ms	361 ms	65 ms
www.thelancet.com/cdn-cgi/challenge-platform/scripts/jsd/main.js	434 ms	413 ms	5.8 ms
securepubads.g.doubleclick.net/tag/js/gpt.js	255 ms	154 ms	18 ms
/wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~selected-le...	211 ms	135 ms	50 ms
/products/marlin/lancet/releasedAssets/js/vendors~lazy-im...	183 ms	121 ms	4.4 ms
/pb-assets/Lancet/homepage/carousel/flickity_lancet_embed...	106 ms	1.9 ms	0.8 ms
www.thelancet.com/pb-assets/Lancet/homepage/carousel/js/flickity.pkgd.js	100 ms	55 ms	24 ms
www.thelancet.com/pb-assets/Lancet/homepage/carousel/js/jquery.js	82 ms	59 ms	16 ms
/beacon.min.js/vcd15cbe7772f49c399c6a5babf22c124171768917...	75 ms	37 ms	6.6 ms
cdn.cookielaw.org/scripttemplates/otSDKStub.js	73 ms	57 ms	5.2 ms
js-agent.newrelic.com/nr-spa-1177.min.js	72 ms	55 ms	7.2 ms
ep2.adtrafficquality.google/sodar/sodar2.js	65 ms	53 ms	4.2 ms
/1/16e2192192?a=916937540&sa=1&v=1177.96a4d39&t=Unnamed%2...	53 ms	52 ms	0.8 ms

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work

Why this matters

Performance issues directly impact user engagement and conversion rates.

Category	Time Spent
Script Evaluation	5.6 s
Style & Layout	2.3 s
Other	1.5 s
Script Parsing & Compilation	734 ms
Rendering	494 ms
Parse HTML & CSS	401 ms
Garbage Collection	171 ms

Many navigations are performed by going back to a previous page, or forwards again. The back/forward cache (bfcache) can speed up these return navigations. Learn more about the bfcache

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failure reason	Failure type
The page has an unload handler in the main frame.	Actionable

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 3.5 KiB

URL	Transfer Size	Est Savings
www.thelancet.com/pb-assets/Lancet/homepage/carousel/css/flickity-docs.css	10.3 KiB	3.5 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
A logo for The Lancet Pulse podcast which features a blue background and white … `div.highlights-img-inner > span > a > img`	/pb-assets/Lancet/homepage/latest_news/latest-news-260411...
Fishermen unload mangrove seedlings that they will plant along a coastal area a… `div.highlights-img-inner > span > a > img`	/pb-assets/Lancet/homepage/latest_news/latest-news-260411...
A medical professional is holding a smear test kit for HPV. Copyright: Peter Da… `div.highlights-img-inner > span > a > img`	/pb-assets/Lancet/homepage/latest_news/latest-news-260411...
Children stacking their hands on top of one another on a grassy field. Copyrigh… `div.highlights-img-inner > span > a > img`	/pb-assets/Lancet/homepage/latest_news/latest-news-260411...
The Lancet Home `div.journal-logos > span > a > img`	www.thelancet.com/pb-assets/ux3/logos/lancet/LANCET-1665147351037.svg
The Lancet logo `div.footer__top > div.footer__logo > a > img`	www.thelancet.com/pb-assets/ux3/logos/lancet/LANCET-1665147351037.svg
Advertisement `div.horizontalAdContainer > div.horizontalAdLabelContainer > div.horizontalAdLabel > img`	www.thelancet.com/templates/jsp/_style2/_marlin/images/bg_adHoriz.gif

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

●Layout shift culprits

●Optimize DOM size

●Forced reflow

●Modern HTTP

●Optimize viewport for mobile

●Avoids enormous network payloads Total size was 2,545 KiB

●Avoid long main-thread tasks 20 long tasks found

●Network Requests

●Network Round Trip Times 20 ms

●Server Backend Latencies 180 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Initial server response time was short Root document took 190 ms

●Avoid large layout shifts 2 layout shifts 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.

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
back `main#pageBody > div.w-slide > div.w-slide_head > a.w-slide__back`

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
Listen to the latest episode of The Lancet Pulse podcast which discusses the wo… `li.publication-list__article > div.publication-list__article__content__wrapper > div.publication-list__article__content > h4#S1470204523006459-title`
Embedding social prescribing in primary care in England and Scotland: a qualita… `section > div.search__item__body > span.hlFld-Title > h4.meta__title`

These are opportunities to improve keyboard navigation in your application.

Best practices

Disabling zooming is problematic for users with low vision who rely on screen magnification to properly see the contents of a web page. Learn more about the viewport meta tag.

Why this matters

Informational: a Permissions-Policy directive showing feature -> allowed origins.

Source: MDN Permissions-Policy

Failing Elements
head > meta `head > meta`

Touch targets with sufficient size and spacing help users who may have difficulty targeting small controls to activate the targets. Learn more about touch targets.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Accessibility `div.align-center > div > p.align-center > a`

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
Cookie settings `div.align-center > div > p.align-center > button#cookieBtn`

○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

●Buttons have an accessible name

●Image elements have `[alt]` attributes

●Form elements have associated labels

●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

●Document has a `<title>` element

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

●`<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

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

●Skip links are focusable.

●Document has a main landmark.

●Deprecated ARIA roles were not used

●Identical links have the same purpose.

○`[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

○`<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

○Select elements have associated label elements.

○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.

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
A logo for The Lancet Pulse podcast which features a blue background and white … `div.highlights-img-inner > span > a > img`	/pb-assets/Lancet/homepage/latest_news/latest-news-260411...	380 x 241	288 x 183	570 x 362
Advertisement `div.horizontalAdContainer > div.horizontalAdLabelContainer > div.horizontalAdLabel > img`	www.thelancet.com/templates/jsp/_style2/_marlin/images/bg_adHoriz.gif	9 x 72	10 x 80	14 x 108

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	/wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~selected-le... line 1, col 2440
StorageType.persistent is deprecated. Please use standardized navigator.storage instead.	www.thelancet.com/cdn-cgi/challenge-platform/scripts/jsd/main.js
Fledge	www.thelancet.com/cdn-cgi/challenge-platform/scripts/jsd/main.js
Unload event listeners are deprecated and will be removed.	www.thelancet.com/ line 11, col 26065

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
/products/marlin/lancet/releasedAssets/fonts/source-sans-...	`Failed to load resource: the server responded with a status of 403 ()`
www.thelancet.com/pb-assets/Lancet/homepage/carousel/fonts/2D333F_2_0.woff2	`Failed to load resource: the server responded with a status of 404 ()`
www.thelancet.com/pb-assets/Lancet/homepage/carousel/fonts/2D333F_1_0.woff2	`Failed to load resource: the server responded with a status of 404 ()`
www.thelancet.com/pb-assets/Lancet/homepage/carousel/fonts/2D333F_2_0.woff	`Failed to load resource: the server responded with a status of 404 ()`
www.thelancet.com/pb-assets/Lancet/homepage/carousel/fonts/2D333F_1_0.woff	`Failed to load resource: the server responded with a status of 404 ()`
/products/marlin/lancet/releasedAssets/js/main.bundle-582... line 8, col 43193	`NetworkError: A network error occurred.`
www.thelancet.com/	SyntaxError: Failed to execute 'appendChild' on 'Node': Unexpected token ':' at HTMLHeadElement.nrWrapper [as appendChild] (https://www.thelancet.com/:12:26066) at m (https://www.thelancet.com/wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~selected-legacy.js:2:880) at ce.globalEval (https://www.thelancet.com/wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~selected-legacy.js:2:3031) at text script (https://www.thelancet.com/wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~selected-legacy.js:2:80994) at https://www.thelancet.com/wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~selected-legacy.js:2:77349 at l (https://www.thelancet.com/wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~selected-legacy.js:2:77466) at XMLHttpRequest.<anonymous> (https://www.thelancet.com/wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~selected-legacy.js:2:80265) at XMLHttpRequest.nrWrapper (https://www.thelancet.com/:12:26066)
www.thelancet.com/ line 3294, col 61	`TypeError: Cannot read properties of null (reading 'getElementsByTagName') at https://www.thelancet.com/:3295:62`

Issues logged to the `Issues` panel in Chrome Devtools indicate unresolved problems. They can come from network request failures, insufficient security controls, and other browser concerns. Open up the Issues panel in Chrome DevTools for more details on each issue.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Issue type
Content security policy

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	Map URL
/products/marlin/lancet/releasedAssets/js/main.bundle-582...	/products/marlin/lancet/releasedAssets/js/main.bundle-582...
/products/marlin/lancet/releasedAssets/js/vendors~lazy-im...	/products/marlin/lancet/releasedAssets/js/vendors~lazy-im...
/products/marlin/lancet/releasedAssets/js/search-31ba933e...	/products/marlin/lancet/releasedAssets/js/search-31ba933e...
/products/marlin/lancet/releasedAssets/js/requestidlecall...	/products/marlin/lancet/releasedAssets/js/requestidlecall...
/products/marlin/lancet/releasedAssets/js/profile-a663aac...	/products/marlin/lancet/releasedAssets/js/profile-a663aac...
/products/marlin/lancet/releasedAssets/js/plumX-f978978bf...	/products/marlin/lancet/releasedAssets/js/plumX-f978978bf...
/products/marlin/lancet/releasedAssets/js/megaMenu-c0b9d6...	/products/marlin/lancet/releasedAssets/js/megaMenu-c0b9d6...
/products/marlin/lancet/releasedAssets/js/lazy-imports-35...	/products/marlin/lancet/releasedAssets/js/lazy-imports-35...
/products/marlin/lancet/releasedAssets/js/dynamic-imports...	/products/marlin/lancet/releasedAssets/js/dynamic-imports...

●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

●Page has the HTML doctype

●Properly defines charset

●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

○Redirects HTTP traffic to HTTPS

○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
Close search options `form > div.quick-search__box > div.quick-search__box-inner > a.quick-search__box-close`

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`