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Lighthouse Desktop

· 0 checks — Desktop Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.
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Detailed Report

Audit breakdown by category with detailed findings.

86

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.

RequestCache TTLTransfer Size
/sites/www/files/styles/ncids_promo_1x1/public/cgov_image...800327.0 s745.0 KiB
assets.adobedtm.com/6a4249cd0a2c/949e98979342/launch-5f2a5357bf66.min.js3600.0 s47.1 KiB
/sites/www/files/ncids_hero/field_widescreen_hero/2023-07...800324.0 s328.2 KiB
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...800326.0 s233.8 KiB
/sites/www/files/styles/video_display_ncids_inline/public...800328.0 s206.2 KiB
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...800327.0 s150.7 KiB
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...800328.0 s138.7 KiB
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...800328.0 s133.5 KiB
/sites/www/files/styles/ncids_promo_1x1/public/cgov_image...800327.0 s121.5 KiB
/sites/www/files/styles/ncids_promo_1x1/public/cgov_image...800327.0 s105.5 KiB
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...800325.0 s100.8 KiB
dap.digitalgov.gov/Universal-Federated-Analytics-Min.js?agency=HHS&subagency=NCI0.0 ms9.4 KiB
/sites/www/files/styles/ncids_guide_card_16x9/public/ncid...800326.0 s88.0 KiB
/sites/www/files/styles/ncids_guide_card_16x9/public/ncid...800326.0 s70.2 KiB
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...800325.0 s63.9 KiB
dap.digitalgov.gov/web-vitals/dist/web-vitals.attribution.iife.js0.0 ms4.5 KiB
script.crazyegg.com/pages/scripts/0076/4407.js300.0 s2.7 KiB
/profiles/custom/cgov_site/themes/custom/ncids_trans/dist...800324.0 s21.6 KiB
/profiles/custom/cgov_site/themes/custom/ncids_trans/dist...800324.0 s20.5 KiB
/profiles/custom/cgov_site/themes/custom/ncids_trans/dist...800324.0 s13.9 KiB
/6a4249cd0a2c/949e98979342/1bd6a83c2894/RC1bcdb10700df439...3600.0 s776 B
/6a4249cd0a2c/949e98979342/1bd6a83c2894/RCcdc0a9518ff54d3...3600.0 s611 B
/profiles/custom/cgov_site/themes/custom/ncids_trans/dist...800324.0 s2.7 KiB
www.cancer.gov/sites/www/files/ncids_header/logos/Logo_NCI.svg798781.0 s1.5 KiB
/sites/www/files/css/css_L5Bo1BLOIOXD6lsbSfG9GpUljueGZgAE...800324.0 s1.4 KiB
/profiles/custom/cgov_site/themes/custom/ncids_trans/dist...798783.0 s526 B
/profiles/custom/cgov_site/themes/custom/ncids_trans/dist...798784.0 s446 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.

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.

URLResource SizeEst Savings
A young, female scientist in a lab coat and gloves examines a sample under a mi… div.tablet-lg:grid-container-widescreen > div.nci-promo-block > picture.nci-promo-block__image > img
/sites/www/files/styles/ncids_promo_1x1/public/cgov_image...744.3 KiB714.4 KiB
Female medical professional reviewing results with a patient and caregiver. div.usa-section > div.nci-hero > picture.nci-hero__image > img
/sites/www/files/ncids_hero/field_widescreen_hero/2023-07...327.7 KiB242.7 KiB
Breast tissue showing substantial changes. li.nci-card > a > picture.nci-card__image > img
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...233.4 KiB218.2 KiB
div.cgdp-video__media > div#ytplayer-jC8CUIID2HA > div.video-preview--container > img div.cgdp-video__media > div#ytplayer-jC8CUIID2HA > div.video-preview--container > img
/sites/www/files/styles/video_display_ncids_inline/public...205.8 KiB158.2 KiB
National Cancer Institute Shady Grove campus. li.nci-card > a > picture.nci-card__image > img
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...150.3 KiB137.8 KiB
Illustration of three scientists having a conversation. li.nci-card > a > picture.nci-card__image > img
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...138.4 KiB132.5 KiB
NCI advisory board members seated around a conference table. li.nci-card > a > picture.nci-card__image > img
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...133.1 KiB122.0 KiB
headshot of Dr. Anthony Letai, NCI Director div.tablet-lg:grid-container-widescreen > div.nci-promo-block > picture.nci-promo-block__image > img
/sites/www/files/styles/ncids_promo_1x1/public/cgov_image...121.1 KiB93.0 KiB
A gloved hand selects labeled blood sample tubes from a rack in a laboratory. li.nci-card > a > picture.nci-card__image > img
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...100.5 KiB92.1 KiB
Representative on a headset helping a patient who has called in for assistance div.tablet-lg:grid-container-widescreen > div.nci-promo-block > picture.nci-promo-block__image > img
/sites/www/files/styles/ncids_promo_1x1/public/cgov_image...105.1 KiB80.7 KiB
Cancer patient and caregiver speaking with a doctor. div.nci-guide-card > div.nci-guide-card__wrapper > picture.nci-guide-card__image > img
/sites/www/files/styles/ncids_guide_card_16x9/public/ncid...87.6 KiB67.4 KiB
A young man with dark black hair and beard, form fitting orange shirt, with his… li.nci-card > a > picture.nci-card__image > img
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...63.6 KiB58.2 KiB
Female researcher writes on a sample vial while sitting by a microscope. div.nci-guide-card > div.nci-guide-card__wrapper > picture.nci-guide-card__image > img
/sites/www/files/styles/ncids_guide_card_16x9/public/ncid...69.8 KiB53.7 KiB

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-1-IMG
nodeLabel: Female medical professional reviewing results with a patient and caregiver.
path: 1,HTML,1,BODY,1,DIV,2,DIV,1,MAIN,0,DIV,0,DIV,0,PICTURE,5,IMG
selector: div.usa-section > div.nci-hero > picture.nci-hero__image > img
snippet: <img loading="eager" src="https://www.cancer.gov/sites/www/files/ncids_hero/field_widescreen_hero/20…" width="640" height="640" alt="Female medical professional reviewing results with a patient and caregiver.">

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.

URLTransfer SizeDuration
/css2?family=Open+Sans:ital,wght@0,300;0,400;0,600;0,700;...3.4 KiB265 ms
/profiles/custom/cgov_site/themes/custom/ncids_trans/dist...21.6 KiB
/profiles/custom/cgov_site/themes/custom/ncids_trans/dist...20.5 KiB
/sites/www/files/css/css_L5Bo1BLOIOXD6lsbSfG9GpUljueGZgAE...1.4 KiB

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: 0.0 ms 39.2 KiB
URLTransfer SizeEst Savings
/profiles/custom/cgov_site/themes/custom/ncids_trans/dist...21.3 KiB20.5 KiB
/profiles/custom/cgov_site/themes/custom/ncids_trans/dist...20.2 KiB18.7 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: 0.0 ms 88.9 KiB
URLTransfer SizeEst Savings
www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L147.2 KiB60.5 KiB
/pages/versioned/common-scripts/4ce8c7df8d425cc5046457682...55.1 KiB28.5 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.

URLTransfer Size
/sites/www/files/styles/ncids_promo_1x1/public/cgov_image...745.0 KiB
/sites/www/files/ncids_hero/field_widescreen_hero/2023-07...328.2 KiB
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...233.8 KiB
/sites/www/files/styles/video_display_ncids_inline/public...206.2 KiB
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...150.7 KiB
www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L147.5 KiB
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...138.7 KiB
/sites/www/files/styles/ncids_featured_16x9/public/cgov_i...133.5 KiB
/sites/www/files/styles/ncids_promo_1x1/public/cgov_image...121.5 KiB
/sites/www/files/styles/ncids_promo_1x1/public/cgov_image...105.5 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
National Cancer Institute Home Page div#extended-mega-logo > a > picture > img
www.cancer.gov/sites/www/files/ncids_header/logos/Logo_NCI.svg

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: 556 ms
URLTime Spent
cancer.gov/556 ms
www.cancer.gov/0.0 ms
●Time to Interactive 1.9 s
●Layout shift culprits
●Optimize DOM size
●Font display
●Forced reflow
●LCP breakdown
●Modern HTTP
●Optimize viewport for mobile
●Max Potential First Input Delay 50 ms
●Minify CSS
●Minify JavaScript
●User Timing marks and measures 9 user timings
●JavaScript execution time 0.2 s
●Minimizes main-thread work 0.5 s
●Avoid long main-thread tasks 1 long task found
●Page didn't prevent back/forward cache restoration
●Network Requests
●Network Round Trip Times 120 ms
●Server Backend Latencies 90 ms
●Tasks
●Diagnostics
●Metrics
●Screenshot Thumbnails
●Final Screenshot
●Script Treemap Data
●Resources Summary
●Initial server response time was short Root document took 20 ms
●Avoid large layout shifts 1 layout shift found
○INP breakdown
○Avoid non-composited animations
97

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
U.S. Department of Health and Human Services div.usa-footer__address > div.usa-footer__contact-info > address > a
National Institutes of Health div.usa-footer__address > div.usa-footer__contact-info > address > a
National Cancer Institute div.usa-footer__address > div.usa-footer__contact-info > address > a
USA.gov div.usa-footer__address > div.usa-footer__contact-info > address > 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
Find a Cancer Type div.nci-guide-card__body > ul.nci-card__button-group > li > a.usa-button
Treatment div.nci-guide-card__body > ul.nci-card__button-group > li > a.usa-button
Side Effects div.nci-guide-card__body > ul.nci-card__button-group > li > a.usa-button
Causes & Prevention div.nci-guide-card__body > ul.nci-card__button-group > li > a.usa-button
Diagnosis & Staging div.nci-guide-card__body > ul.nci-card__button-group > li > a.usa-button
Find a Clinical Trial div.nci-guide-card__body > ul.nci-card__button-group > li > a.usa-button
Funding Opportunities div.nci-guide-card__body > ul.nci-card__button-group > li > a.usa-button
Resources for Researchers div.nci-guide-card__body > ul.nci-card__button-group > li > a.usa-button
Apply for a Grant div.nci-guide-card__body > ul.nci-card__button-group > li > a.usa-button
Find a Research Contact div.nci-guide-card__body > ul.nci-card__button-group > li > a.usa-button
New Blood Test May Detect Early Pancreatic Cancer Four-marker blood test could… div.grid-container > ul.nci-card-group > li.nci-card > a
Why Are Cancer Diagnoses Rising in People Under Age 50? Researchers are lookin… div.grid-container > ul.nci-card-group > li.nci-card > a
Predicting Breast Cancer Aggressiveness Substantial changes in breast tissue m… div.grid-container > ul.nci-card-group > li.nci-card > a
Get Started div.tablet-lg:grid-container-widescreen > div.nci-promo-block > div.nci-promo-block__content > a.usa-button
Senior Leaders Information about NCI senior leadership. div.grid-container > ul.nci-card-group > li.nci-card > a
NCI Divisions, Offices, and Centers NCI has 30 divisions, offices, and centers… div.grid-container > ul.nci-card-group > li.nci-card > a
Advisory Boards and Review Groups NCI relies on advisory committees to provide… div.grid-container > ul.nci-card-group > li.nci-card > a
The Power of Improved Data Sharing - Childhood Cancer Data Initiative figure.cgdp-video__figure > div.cgdp-video__media > div#ytplayer-jC8CUIID2HA > div.video-preview--container
○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
●`[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
●No element has a `[tabindex]` value greater than 0
●Heading elements appear in a sequentially-descending order
●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
○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
○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.
○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.
100

Best Practices

●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 browser errors logged to the console
●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
●Page has valid source maps
○Redirects HTTP traffic to HTTPS
○Use a strong HSTS policy
○Mitigate clickjacking with XFO or CSP
○Detected JavaScript libraries
92

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 destinationLink Text
www.cancer.gov/about-nci/leadership/directorRead More
www.cancer.gov/research/leading-progressLearn 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`

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