Lighthouse Desktop
· 0 checks — Desktop Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.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.
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
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.
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.
Performance issues directly impact user engagement and conversion rates.
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.
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.
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.
Performance issues directly impact user engagement and conversion rates.
Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size
Performance issues directly impact user engagement and conversion rates.
| URL | Resource Size | Est Savings | |
|---|---|---|---|
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/3034105075962818447 | 109.7 KiB | 99.0 KiB |
A community meeting at a Health and Wellness Centre in Nazardih village, Nawada… div.do-card > div.do-item-media > a > img | /do/10.1016/4f9d9162-93c9-4d6f-ac08-283f4e73cd6d/single_c... | 99.3 KiB | 92.0 KiB |
Cancer cells under an automated fluorescence microscope div.do-card > div.do-item-media > a > img | /do/10.1016/a7d423f9-578d-40e1-89a3-8addecd9517e/single_c... | 90.3 KiB | 83.0 KiB |
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 |
Female doctor holding hands of stressed patient while consoling at clinic div.do-card > div.do-item-media > a > img | /do/10.1016/2e3f8d55-c132-448b-8470-b6492f45d646/single_c... | 55.0 KiB | 47.7 KiB |
A boy looking at a single electric lightbulb, powered by solar technology, as i… div.do-card > div.do-item-media > a > img | /do/10.1016/04f8c4ae-ce4a-414f-9e8c-da80cc73d001/single_c... | 55.7 KiB | 47.5 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 |
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.
Performance issues directly impact user engagement and conversion rates.
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.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Duration |
|---|---|---|
| /wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~selected-le... | 68.3 KiB | 314 ms |
| cdn.cookielaw.org/scripttemplates/otSDKStub.js | 9.1 KiB | 262 ms |
| fonts.googleapis.com/css?family=Open+Sans | 2.0 KiB | 216 ms |
| www.thelancet.com/wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~product.css | 13.4 KiB | 68 ms |
| /wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~selected-le... | 4.1 KiB | 68 ms |
| www.thelancet.com/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js | 800 B | 150 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.
Performance issues directly impact user engagement and conversion rates.
| URL | Time Spent |
|---|---|
| thelancet.com/ | 383 ms |
| /as/authorization.oauth2?platSite=LT%2Fthelancet&response... | 301 ms |
| /callback?red_uri=%2F&code=Sst7dXe1Qp01Q5QFUmVnCG3PS_5YrL... | 168 ms |
| www.thelancet.com/ | 0.0 ms |
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
Performance issues directly impact user engagement and conversion rates.
| Element | Layout shift score |
|---|---|
The Lancet
AI in primary care: innovations and challenges
Latest news and comme… body.pb-ui > div#pb-page-content > div > main#pageBody | 0.081 |
The Lancet
AI in primary care: innovations and challenges
Latest news and comme… body.pb-ui > div#pb-page-content > div > main#pageBody | 0.059 |
NEW PODCAST
Listen to the latest episode of The Lancet Pulse podcast which disc… div.container > div.row > div.col-xs-12 > div.highlights-art-layout-outer | 0.058 |
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.
Performance issues directly impact user engagement and conversion rates.
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.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| /products/marlin/lancet/releasedAssets/css/build-02c4f504... | 103.6 KiB | 100.1 KiB |
| 25.3 KiB | 21.1 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.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| /products/marlin/lancet/releasedAssets/js/main.bundle-582... | 216.4 KiB | 148.4 KiB |
| /pagead/managed/js/gpt/m202604160201/pubads_impl.js | 187.7 KiB | 100.4 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 | 57.5 KiB |
| /wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~selected-le... | 68.0 KiB | 51.5 KiB |
| /pagead/managed/js/activeview/current/ufs_web_display.js | 73.1 KiB | 31.0 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.
Performance issues directly impact user engagement and conversion rates.
| URL | Total CPU Time | Script Evaluation | Script Parse |
|---|---|---|---|
| www.thelancet.com/ | 1.1 s | 390 ms | 12 ms |
| Unattributable | 312 ms | 54 ms | 0.0 ms |
| /pagead/managed/js/gpt/m202604160201/pubads_impl.js | 307 ms | 238 ms | 33 ms |
| /products/marlin/lancet/releasedAssets/js/main.bundle-582... | 233 ms | 143 ms | 37 ms |
| /pagead/managed/js/activeview/current/ufs_web_display.js | 132 ms | 105 ms | 12 ms |
| www.thelancet.com/cdn-cgi/challenge-platform/scripts/jsd/main.js | 117 ms | 112 ms | 1.3 ms |
| cdn.cookielaw.org/scripttemplates/202505.2.0/otBannerSdk.js | 110 ms | 70 ms | 22 ms |
| /products/marlin/lancet/releasedAssets/js/lazy-imports-35... | 58 ms | 38 ms | 1.8 ms |
| /wro/f03726d8be65c99af4dc13935c7996e819a5ff0d~selected-le... | 50 ms | 30 ms | 14 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
Performance issues directly impact user engagement and conversion rates.
| Category | Time Spent |
|---|---|
| Script Evaluation | 1.4 s |
| Style & Layout | 583 ms |
| Other | 377 ms |
| Script Parsing & Compilation | 189 ms |
| Rendering | 131 ms |
| Parse HTML & CSS | 106 ms |
| Garbage Collection | 22 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
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.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| www.thelancet.com/pb-assets/Lancet/homepage/carousel/css/flickity-docs.css | 10.3 KiB | 3.5 KiB |
Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.
Performance issues directly impact user engagement and conversion rates.
| 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() { … | 11.6 KiB | 6.5 KiB |
Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions
Performance issues directly impact user engagement and conversion rates.
| URL | |
|---|---|
Cancer cells under an automated fluorescence microscope div.do-card > div.do-item-media > a > img | /do/10.1016/a7d423f9-578d-40e1-89a3-8addecd9517e/single_c... |
A community meeting at a Health and Wellness Centre in Nazardih village, Nawada… div.do-card > div.do-item-media > a > img | /do/10.1016/4f9d9162-93c9-4d6f-ac08-283f4e73cd6d/single_c... |
Female doctor holding hands of stressed patient while consoling at clinic div.do-card > div.do-item-media > a > img | /do/10.1016/2e3f8d55-c132-448b-8470-b6492f45d646/single_c... |
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... |
A boy looking at a single electric lightbulb, powered by solar technology, as i… div.do-card > div.do-item-media > a > img | /do/10.1016/04f8c4ae-ce4a-414f-9e8c-da80cc73d001/single_c... |
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.
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.
ARIA
Some ARIA parent roles must contain specific child roles to perform their intended accessibility functions. Learn more about roles and required children elements.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
Journals
Publish
Clinical
Global health
Multimedia
Events
About div.widget-body > nav#mega-menu-nav > div.mega-menu-nav__wrapper > ul#mega-menu-box |
These are opportunities to improve the usage of ARIA in your application which 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.
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.
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.
Informational: a Permissions-Policy directive showing feature -> allowed origins.
Source: MDN Permissions-Policy
| Failing Elements |
|---|
head > meta head > meta |
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.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
Cookie settings div.align-center > div > p.align-center > button#cookieBtn |
Best Practices
General
Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.
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. | |
| Fledge | |
| 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
Performance issues directly impact user engagement and conversion rates.
| Source | Description |
|---|---|
Failed to load resource: the server responded with a status of 403 () | |
Failed to load resource: the server responded with a status of 404 () | |
Failed to load resource: the server responded with a status of 404 () | |
Failed to load resource: the server responded with a status of 404 () | |
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. |
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.
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.
Performance issues directly impact user engagement and conversion rates.
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
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.