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.

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
players.brightcove.net/1611106632001/default_default/index.min.js	300.0 s	169.5 KiB

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.

A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:source label:Top function call valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]

items: [map[reflowTime:20.165 source:map[column:3278 line:9 type:source-location url:https://players.brightcove.net/1611106632001/default_default/index.min.js urlProvider:network]]]

headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]

items: [map[reflowTime:2.019 source:map[column:25265 line:7 type:source-location url:https://players.brightcove.net/1611106632001/default_default/index.min.js urlProvider:network]] map[reflowTime:8.771 source:map[column:18725 line:1 type:source-location url:https://players.brightcove.net/1611106632001/default_default/index.min.js urlProvider:network]] map[reflowTime:0.357 source:map[type:text value:[unattributed]]] map[reflowTime:20.165 source:map[column:19017 line:1 type:source-location url:https://players.brightcove.net/1611106632001/default_default/index.min.js urlProvider:network]] map[reflowTime:1.266 source:map[column:13978 line:0 type:source-location url:https://www.merck.com/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/js/scripts.min.js?ver=1776849258 urlProvider:network]] map[reflowTime:0.235 source:map[column:14012 line:0 type:source-location url:https://www.merck.com/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/js/scripts.min.js?ver=1776849258 urlProvider:network]] map[reflowTime:0.476 source:map[column:16095 line:0 type:source-location url:https://www.merck.com/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/js/scripts.min.js?ver=1776849258 urlProvider:network]] map[reflowTime:5.421 source:map[column:408 line:0 type:source-location url:https://www.merck.com/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/blocks/mccberg/b24-homepage-no-hero-block/js/index.js?ver=1764577519 urlProvider:network]] map[reflowTime:0.613 source:map[column:5114 line:0 type:source-location url:https://www.merck.com/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/js/tinyslider.min.js?ver=1764577519 urlProvider:network]] map[reflowTime:0.573 source:map[column:5480 line:0 type:source-location url:https://www.merck.com/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/js/tinyslider.min.js?ver=1764577519 urlProvider:network]] map[reflowTime:0.68 source:map[column:5960 line:0 type:source-location url:https://www.merck.com/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/js/tinyslider.min.js?ver=1764577519 urlProvider:network]] map[reflowTime:0.14 source:map[column:6391 line:0 type:source-location url:https://www.merck.com/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/js/tinyslider.min.js?ver=1764577519 urlProvider:network]] map[reflowTime:1.08 source:map[column:16716 line:0 type:source-location url:https://www.merck.com/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/js/tinyslider.min.js?ver=1764577519 urlProvider:network]] map[reflowTime:0.845 source:map[column:12702 line:0 type:source-location url:https://www.merck.com/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/js/tinyslider.min.js?ver=1764577519 urlProvider:network]]]

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-VIDEO

nodeLabel: div#mco-b25-block-block_575ab70bc6e244ddefc011d419eca6da > div.mco-b25-block__media-wrapper > div#brightcove-player-mco-b25-block-block_575ab70bc6e244ddefc011d419eca6da > video#brightcove-player-mco-b25-block-block_575ab70bc6e244ddefc011d419eca6da_html5_api

path: 1,HTML,1,BODY,1,DIV,3,DIV,0,DIV,0,DIV,0,MAIN,0,ARTICLE,0,DIV,0,DIV,0,DIV,0,DIV,0,VIDEO

selector: div#mco-b25-block-block_575ab70bc6e244ddefc011d419eca6da > div.mco-b25-block__media-wrapper > div#brightcove-player-mco-b25-block-block_575ab70bc6e244ddefc011d419eca6da > video#brightcove-player-mco-b25-block-block_575ab70bc6e244ddefc011d419eca6da_html5_api

snippet: <video autoplay="" muted="muted" loop="" id="brightcove-player-mco-b25-block-block_575ab70bc6e244ddefc011d419eca6da_htm…" data-account="1611106632001" data-video-id="6392644500112" data-player="default" data-embed="default" class="vjs-tech" aria-hidden="true" tabindex="-1" poster="https://cf-images.us-east-1.prod.boltdns.net/v1/jit/1611106632001/bc03b5f3…" src="blob:https://www.merck.com/fa87dd9d-9a71-4262-b2a5-8cff7782053a">

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

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
Image for Patients `div.mco-featured-stories-e1-content-item-image-container > a > picture > img.lazyload`	/wp-content/uploads/sites/124/2025/10/Family-preparing-di...	1.9 MiB	1.9 MiB
Image for Health awareness `div.mco-featured-stories-e1-content-item-image-container > a > picture > img.lazyload`	/wp-content/uploads/sites/124/2025/05/DebunkingCancerRecu...	114.1 KiB	107.9 KiB
Image for Health awareness `div.mco-featured-stories-e1-content-item-image-container > a > picture > img.lazyload`	/wp-content/uploads/sites/124/2021/11/Granado-and-family....	58.9 KiB	44.2 KiB
Image for Health awareness `div.mco-b24-homepage-block-image-container > a > picture > img.lazyload`	/wp-content/uploads/sites/124/2025/10/Jon-Michaels.jpg?re...	86.5 KiB	27.0 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.merck.com/wp-includes/css/dist/block-library/style.min.css?ver=6.8.5	15.5 KiB
/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/css/foote...	1.6 KiB
/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/css/botto...	674 B
/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/css/masth...	3.9 KiB
/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/css/style...	9.6 KiB
/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/css/defau...	573 B
/wp-content/mu-plugins/qm-plugins/qm-object-cache/css/sty...	823 B

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

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: 40 ms 26.9 KiB

URL	Transfer Size	Est Savings
www.merck.com/wp-includes/css/dist/block-library/style.min.css?ver=6.8.5	15.2 KiB	15.2 KiB
.bc-iframe,.bc-iframe body{height:100%;margin:0;padding:0;width:100%;overflow:hidden} …	12.6 KiB	11.7 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: 80 ms 129.7 KiB

URL	Transfer Size	Est Savings
www.googletagmanager.com/gtm.js?id=GTM-M74WZDM	187.0 KiB	74.8 KiB
players.brightcove.net/1611106632001/default_default/index.min.js	169.0 KiB	54.9 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
/media/v1/hls/v4/clear/1611106632001/bc03b5f3-ab97-4863-b...	2.1 MiB
/media/v1/hls/v4/clear/1611106632001/bc03b5f3-ab97-4863-b...	1.9 MiB
/wp-content/uploads/sites/124/2025/10/Family-preparing-di...	1.9 MiB
/media/v1/hls/v4/clear/1611106632001/bc03b5f3-ab97-4863-b...	1.4 MiB
/media/v1/hls/v4/clear/1611106632001/bc03b5f3-ab97-4863-b...	1.4 MiB
/media/v1/hls/v4/clear/1611106632001/bc03b5f3-ab97-4863-b...	1.3 MiB
/media/v1/hls/v4/clear/1611106632001/bc03b5f3-ab97-4863-b...	1.1 MiB
www.googletagmanager.com/gtm.js?id=GTM-M74WZDM	187.3 KiB
players.brightcove.net/1611106632001/default_default/index.min.js	169.5 KiB
/wp-content/uploads/sites/124/2025/05/DebunkingCancerRecu...	114.5 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
Image for Health awareness `div.mco-b24-homepage-block-image-container > a > picture > img.lazyload`	/wp-content/uploads/sites/124/2025/10/Jon-Michaels.jpg?re...
div.mco-three-column-content-col-img-container > div.mco-three-column-content-col-img > picture > img.lazyload `div.mco-three-column-content-col-img-container > div.mco-three-column-content-col-img > picture > img.lazyload`	/wp-content/uploads/sites/124/2025/10/patients.jpg?resize...
Woman scientist injecting solution into test tube `div.mco-three-column-content-col-img-container > div.mco-three-column-content-col-img > picture > img.lazyload`	/wp-content/uploads/sites/124/2020/03/B10-Investor-relati...
Image showing microbes in a lab dish on the left and earth on the right `div.mco-three-column-content-col-img-container > div.mco-three-column-content-col-img > picture > img.lazyload`	/wp-content/uploads/sites/124/2025/08/2025_ImpactReport_C...
Outside of corporate building with blue windows `a > div.related-content-item-image-contianer > picture > img.lazyload`	/wp-content/uploads/sites/124/2020/04/B2-Our-latest-news-...
rahway headquarters `a > div.related-content-item-image-contianer > picture > img.lazyload`	/wp-content/uploads/sites/124/2024/03/Headquarters_Rahway...
Image showing microbes in a lab dish on the left and earth on the right `a > div.related-content-item-image-contianer > picture > img.lazyload`	/wp-content/uploads/sites/124/2025/08/2025_ImpactReport_C...
Image for Patients `div.mco-featured-stories-e1-content-item-image-container > a > picture > img.lazyload`	/wp-content/uploads/sites/124/2025/10/Family-preparing-di...
Image for Health awareness `div.mco-featured-stories-e1-content-item-image-container > a > picture > img.lazyload`	/wp-content/uploads/sites/124/2021/11/Granado-and-family....
Image for Health awareness `div.mco-featured-stories-e1-content-item-image-container > a > picture > img.lazyload`	/wp-content/uploads/sites/124/2025/05/DebunkingCancerRecu...
Image for Patients `div.mco-featured-stories-e1-content-item-image-container > a > picture > img.lazyload`	/wp-content/uploads/sites/124/2025/10/Family-preparing-di...
Image for Health awareness `div.mco-featured-stories-e1-content-item-image-container > a > picture > img.lazyload`	/wp-content/uploads/sites/124/2021/11/Granado-and-family....
Site logo `div.site-branding > p.site-title > a#micro-site-logo > img.site-logo`	www.merck.com/wp-content/uploads/sites/124/2025/08/site-logo.svg
div#mastheadMenu > button#siteSearchToggle > span.menu-toggle-text-open > img `div#mastheadMenu > button#siteSearchToggle > span.menu-toggle-text-open > img`	/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/images/se...
div#mastheadMenu > button#siteNavigationToggle > span.menu-toggle-text-open > img `div#mastheadMenu > button#siteNavigationToggle > span.menu-toggle-text-open > img`	/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/images/bu...
pause video `div.mco-b25-block__video-btns > div.mco-b25-block__video-btn > div.mco-b25-block__btn-pause > img.mco-b25-block__btn-pause-icon`	/wp-content/themes/cex-wpvip-mhh-mhh2-mcc-theme/images/pa...
Twitter icon `div.social-icons-row > div.social-icons > a > img.lazyload`
Facebook icon `div.social-icons-row > div.social-icons > a > img.lazyload`
Linkedin icon `div.social-icons-row > div.social-icons > a > img.lazyload`
Instagram icon `div.social-icons-row > div.social-icons > a.external-link-with-popup > img.lazyload`
YouTube icon `div.social-icons-row > div.social-icons > a.external-link-with-popup > img.lazyload`

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

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: 380 ms

URL	Time Spent
merck.com/	380 ms
www.merck.com/	0.0 ms

Keep the server response time for the main document short because all other requests depend on it. Learn more about the Time to First Byte metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 561 ms

URL	Time Spent
www.merck.com/	661 ms

●Time to Interactive 1.6 s

●Layout shift culprits

●Optimize DOM size

●Font display

●LCP breakdown

●Modern HTTP

●Optimize viewport for mobile

●Max Potential First Input Delay 40 ms

●Minify CSS

●Minify JavaScript

●User Timing marks and measures 3 user timings

●JavaScript execution time 0.3 s

●Minimizes main-thread work 0.6 s

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 30 ms

●Server Backend Latencies 180 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Avoid large layout shifts 2 layout shifts found

○INP breakdown

○Avoid long main-thread tasks

○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

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
Cookie Preferences `div.menu-footer-menu-container > ul#menuFooter > li.menu-item > button#menu-item-763862`

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-*]` 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

●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.

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

●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

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

●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements

●Heading elements appear in a sequentially-descending order

●Document has a main landmark.

●Deprecated ARIA roles were not used

●All heading elements contain content.

●Identical links have the same purpose.

○`[accesskey]` values are unique

○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 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

○`<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

○Form elements have associated labels

○Links are distinguishable without relying on color.

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

○`<object>` elements have alternate text

○Select elements have associated label elements.

○Skip links are focusable.

○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.

○`[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>`.

○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.

Best Practices

Trust and Safety

All sites should be protected with HTTPS, even ones that don't handle sensitive data. This includes avoiding mixed content, where some resources are loaded over HTTP despite the initial request being served over HTTPS. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs. Learn more about HTTPS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Insecure URL	Request Resolution
/thumbnail/v1/1611106632001/bc03b5f3-ab97-4863-bd4f-2352f...	Allowed

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

Source	Description
players.brightcove.net/1611106632001/default_default/index.min.js line 8, col 19007	`Connecting to 'http://manifest.prod.boltdns.net/thumbnail/v1/1611106632001/bc03b5f3-ab97-4863-bd4f-2352fb869668/1fb1d75d-a6b0-4bb8-9e71-a8ebd2010347/thumbnail.webvtt?fastly_token=NjllOWE1MmNfZDY5YmM0NDVmZmZhYTNlM2M2ZTA2M2EwMjY4Y2NkZGI5MWQxNmU0YzIzOTk0MmNjNjIzZmQ3NDM3ZTYyMzNhMQ%3D%3D' violates the following Content Security Policy directive: "default-src 'self' https: wss:". Note that 'connect-src' was not explicitly set, so 'default-src' is used as a fallback. The action has been blocked.`
players.brightcove.net/1611106632001/default_default/index.min.js line 8, col 4680	`VIDEOJS: ERROR: Error: Internal XMLHttpRequest Error at j (https://players.brightcove.net/1611106632001/default_default/index.min.js:9:17845) at XMLHttpRequest.d (https://players.brightcove.net/1611106632001/default_default/index.min.js:9:17204) [object Object]`

players.brightcove.net/1611106632001/default_default/index.min.js line 8, col 19007

Connecting to 'http://manifest.prod.boltdns.net/thumbnail/v1/1611106632001/bc03b5f3-ab97-4863-bd4f-2352fb869668/1fb1d75d-a6b0-4bb8-9e71-a8ebd2010347/thumbnail.webvtt?fastly_token=NjllOWE1MmNfZDY5YmM0NDVmZmZhYTNlM2M2ZTA2M2EwMjY4Y2NkZGI5MWQxNmU0YzIzOTk0MmNjNjIzZmQ3NDM3ZTYyMzNhMQ%3D%3D' violates the following Content Security Policy directive: "default-src 'self' https: wss:". Note that 'connect-src' was not explicitly set, so 'default-src' is used as a fallback. The action has been blocked.

players.brightcove.net/1611106632001/default_default/index.min.js line 8, col 4680

VIDEOJS: ERROR: Error: Internal XMLHttpRequest Error
    at j (https://players.brightcove.net/1611106632001/default_default/index.min.js:9:17845)
    at XMLHttpRequest.d (https://players.brightcove.net/1611106632001/default_default/index.min.js:9:17204) [object Object]

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

●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

●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

●Page has valid source maps

○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.

Content Best Practices

Descriptive link text helps search engines understand your content. Learn how to make links more accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Link destination	Link Text
www.merck.com/company-overview/	Learn more

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

●Document has a meta description

●Page has successful HTTP status code

●Links are crawlable

●robots.txt is valid

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

●Document has a valid `rel=canonical`