Skip to content
https://doxygen.org

Lighthouse Desktop

· 0 checks — Desktop Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.
SCORE
0
GRADE
FIX
0
REVIEW
0
PASS
0
INFO
0

Detailed Report

Audit breakdown by category with detailed findings.

84

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
www.doxygen.nl/assets/cplusplus_image_perspective.png604800.0 s528.9 KiB
www.doxygen.nl/assets/DoxygenExample_dark.png604800.0 s442.7 KiB
www.doxygen.nl/assets/DoxygenExample_light.png604800.0 s440.5 KiB
www.doxygen.nl/assets/config_demo.png604800.0 s260.7 KiB
/pagead/managed/js/adsense/m202604170101/show_ads_impl_fy...1209600.0 s177.5 KiB
www.doxygen.nl/assets/cross_referencing_demo.png604800.0 s139.2 KiB
www.doxygen.nl/assets/markdown_demo.png604800.0 s121.7 KiB
buttons.github.io/buttons.js600.0 s7.0 KiB
/kraXZubvzhGJqPW-dc-EXBUhg7T9Pv-K7z42ONaoq87-iEbv5NNS4cYF...86400.0 s15.2 KiB
/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da177152312...86400.0 s10.7 KiB
www.doxygen.nl/bootstrap.min.css604800.0 s28.2 KiB
www.doxygen.nl/bootstrap.min.js604800.0 s16.2 KiB
www.paypalobjects.com/en_GB/i/btn/btn_donate_SM.gif3600.0 s1.9 KiB
www.doxygen.nl/assets/multiple_formats.svg604800.0 s7.5 KiB
www.doxygen.nl/tocbot.min.js604800.0 s4.0 KiB
www.doxygen.nl/assets/doxygen.svg604800.0 s4.0 KiB
www.doxygen.nl/assets/diagrams_demo.svg604800.0 s3.3 KiB
www.doxygen.nl/doxygen_homepage.css604800.0 s2.6 KiB
www.doxygen.nl/assets/config.svg604800.0 s2.1 KiB
www.doxygen.nl/assets/cross_referencing.svg604800.0 s2.1 KiB
www.doxygen.nl/assets/documents.svg604800.0 s1.1 KiB
www.doxygen.nl/assets/cplusplus.svg604800.0 s1.1 KiB
www.doxygen.nl/assets/markdown.svg604800.0 s994 B
www.doxygen.nl/tocbot.min.css604800.0 s879 B
www.doxygen.nl/assets/diagrams.svg604800.0 s853 B
www.doxygen.nl/assets/download.svg604800.0 s761 B
www.doxygen.nl/doxygen_homepage.js604800.0 s723 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.

URLEst Savings
/s/opensans/v13/cJZKeOuBrn4kERxqtaUH3T8E0i7KZn-EPnyo3HZu7...40 ms
/s/opensans/v13/DXI1ORHCpsQm3Vp6mXoaTXhCUOGz7vYGh680lGh-u...40 ms
/s/opensans/v40/memvYaGs126MiZpBA-UvWbX2vVnXBbObj2OVTS-mu...35 ms

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:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:44.03 source:map[type:text value:[unattributed]]] map[reflowTime:0.122 source:map[column:389 line:67 type:source-location url:https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js?client=ca-pub-1917318012276499 urlProvider:network]] map[reflowTime:0.134 source:map[column:425 line:181 type:source-location url:https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js?client=ca-pub-1917318012276499 urlProvider:network]]]

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
div#cplusplus > div.row > div.d-flex > img div#cplusplus > div.row > div.d-flex > img
www.doxygen.nl/assets/cplusplus_image_perspective.png528.2 KiB499.8 KiB
Dark div.screenshot > div.screenshot > div.images-container > img#darkimage
www.doxygen.nl/assets/DoxygenExample_dark.png442.1 KiB384.2 KiB
Light div.screenshot > div.screenshot > div.images-container > img#lightimage
www.doxygen.nl/assets/DoxygenExample_light.png439.8 KiB382.2 KiB
div#config > div.row > div.d-flex > img div#config > div.row > div.d-flex > img
www.doxygen.nl/assets/config_demo.png260.0 KiB223.1 KiB
div#crossreferencing > div.row > div.d-flex > img div#crossreferencing > div.row > div.d-flex > img
www.doxygen.nl/assets/cross_referencing_demo.png138.5 KiB109.6 KiB
div#markdown > div.row > div.d-flex > img div#markdown > div.row > div.d-flex > img
www.doxygen.nl/assets/markdown_demo.png121.1 KiB100.3 KiB
Welcome to doxygen.nl div.fc-header > div.fc-header > div.fc-header-image-container > img.fc-header-image
/kraXZubvzhGJqPW-dc-EXBUhg7T9Pv-K7z42ONaoq87-iEbv5NNS4cYF...14.9 KiB12.7 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-2-IMG
nodeLabel: Light
path: 1,HTML,1,BODY,0,DIV,2,DIV,0,DIV,1,DIV,0,DIV,0,DIV,0,DIV,1,IMG
selector: div.screenshot > div.screenshot > div.images-container > img#lightimage
snippet: <img id="lightimage" class="light-image" src="assets/DoxygenExample_light.png" alt="Light">

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

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
www.doxygen.nl/bootstrap.min.css28.2 KiB131 ms
www.doxygen.nl/doxygen_homepage.css2.6 KiB192 ms
www.doxygen.nl/tocbot.min.css879 B192 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: 496 ms
URLTime Spent
doxygen.org/306 ms
www.doxygen.nl/190 ms
www.doxygen.nl/0.0 ms

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

Diagnostics

Reduce unused 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 39.9 KiB
URLTransfer SizeEst Savings
www.doxygen.nl/bootstrap.min.css27.7 KiB25.9 KiB
.fc-consent-root .fc-dialog-container.fc-fullscreen { height: 100% !important; … } …16.2 KiB14.0 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 205.4 KiB
URLTransfer SizeEst Savings
/pagead/managed/js/adsense/m202604170101/show_ads_impl_fy...177.5 KiB147.9 KiB
/i/ca-pub-1917318012276499?href=https%3A%2F%2Fwww.doxygen...68.8 KiB36.0 KiB
/pagead/js/adsbygoogle.js?client=ca-pub-191731801227649954.4 KiB21.5 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
div#config > div.row > div.d-flex > img div#config > div.row > div.d-flex > img
www.doxygen.nl/assets/config_demo.png
div#cplusplus > div.row > div.d-flex > img div#cplusplus > div.row > div.d-flex > img
www.doxygen.nl/assets/cplusplus_image_perspective.png
div#crossreferencing > div.row > div.d-flex > img div#crossreferencing > div.row > div.d-flex > img
www.doxygen.nl/assets/cross_referencing_demo.png
div#markdown > div.row > div.d-flex > img div#markdown > div.row > div.d-flex > img
www.doxygen.nl/assets/markdown_demo.png
div#diagrams > div.row > div.d-flex > img div#diagrams > div.row > div.d-flex > img
www.doxygen.nl/assets/diagrams_demo.svg
div#multiformat > div.row > div.d-flex > img div#multiformat > div.row > div.d-flex > img
www.doxygen.nl/assets/multiple_formats.svg

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

●Max Potential First Input Delay 70 ms
●Layout shift culprits
●Optimize DOM size
●LCP breakdown
●Modern HTTP
●Optimize viewport for mobile
●Minify CSS
●Minify JavaScript
●Avoids enormous network payloads Total size was 2,541 KiB
●JavaScript execution time 0.1 s
●Minimizes main-thread work 0.6 s
●Avoid long main-thread tasks 2 long tasks found
●Page didn't prevent back/forward cache restoration
●Network Requests
●Network Round Trip Times 30 ms
●Server Backend Latencies 200 ms
●Tasks
●Diagnostics
●Metrics
●Screenshot Thumbnails
●Final Screenshot
●Script Treemap Data
●Resources Summary
●Initial server response time was short Root document took 80 ms
●Avoid large layout shifts 3 layout shifts found
○INP breakdown
○User Timing marks and measures
○Avoid non-composited animations
82

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
Docs div#navbarText > ul.navbar-nav > li.nav-item > a.nav-link
Changelog div#navbarText > ul.navbar-nav > li.nav-item > a.nav-link
Extensions div#navbarText > ul.navbar-nav > li.nav-item > a.nav-link
Examples div#navbarText > ul.navbar-nav > li.nav-item > a.nav-link
Learn more div.fc-dialog-content > div.fc-dialog-scrollable-content > button.fc-faq-header > span.fc-faq-label
List of partners. div.fc-dialog-scrollable-content > div.fc-footer > p > a.fc-vendors-list-dialog

Low-contrast text is difficult or impossible for many users to read. Link text that is discernible improves the experience for users with low vision. Learn how to make links distinguishable.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Version 1.16.1 div.row > div.d-flex > p.message > a#banner-link-updates

These are opportunities to improve the legibility of your content.

Names and labels

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div#multiformat > div.row > div.d-flex > img div#multiformat > div.row > div.d-flex > img
div#markdown > div.row > div.d-flex > img div#markdown > div.row > div.d-flex > img
div#cplusplus > div.row > div.d-flex > img div#cplusplus > div.row > div.d-flex > img
div#crossreferencing > div.row > div.d-flex > img div#crossreferencing > div.row > div.d-flex > img
div#diagrams > div.row > div.d-flex > img div#diagrams > div.row > div.d-flex > img
div#config > div.row > div.d-flex > img div#config > div.row > div.d-flex > img

Form elements without effective labels can create frustrating experiences for screen reader users. Learn more about the `select` element.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
€ (EUR) $ (USD) tbody > tr > td.currency > select

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Best practices

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
home cleaning div.col-md-4 > ul.list-unstyled > li > a
bookmakers div.col-md-4 > ul.list-unstyled > li > a
Domestic cleaning service div.col-md-4 > ul.list-unstyled > li > a
onlinecasino.amsterdam div.col-md-4 > ul.list-unstyled > li > a

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
●`<input type="image">` elements have `[alt]` text
●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.
●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
●`<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
●Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.
●Heading elements appear in a sequentially-descending order
●Document has a main landmark.
●Deprecated ARIA roles were not used
●Uses ARIA roles only on compatible elements
●Elements with visible text labels have matching accessible names.
○`[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
○`<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.
○The document does not use `<meta http-equiv="refresh">`
○`<object>` elements have alternate text
○Skip links are focusable.
○`<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.
○Image elements do not have `[alt]` attributes that are redundant text.
○Identical links have the same purpose.
○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.
○`<td>` elements in a large `<table>` have one or more table headers.
62

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 URLRequest Resolution
www.doxygen.nl/Allowed

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 / WarningSource
Specifying overflow: visible on img, video and canvas tags may cause them to produce visual content outside of the element bounds. See https://github.com/WICG/shared-element-transitions/blob/main/debugging_overflow_on_images.md.
/_/mss/boq-content-ads-contributor/_/js/k=boq-content-ads... line 19, col 449
●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
●Use a strong HSTS policy
●Ensure proper origin isolation with COOP
●Mitigate DOM-based XSS with Trusted Types
●Page has valid source maps
○Redirects HTTP traffic to HTTPS
○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

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div#multiformat > div.row > div.d-flex > img div#multiformat > div.row > div.d-flex > img
div#markdown > div.row > div.d-flex > img div#markdown > div.row > div.d-flex > img
div#cplusplus > div.row > div.d-flex > img div#cplusplus > div.row > div.d-flex > img
div#crossreferencing > div.row > div.d-flex > img div#crossreferencing > div.row > div.d-flex > img
div#diagrams > div.row > div.d-flex > img div#diagrams > div.row > div.d-flex > img
div#config > div.row > div.d-flex > img div#config > div.row > div.d-flex > img

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 have descriptive text
●Links are crawlable
●robots.txt is valid
●Document has a valid `hreflang`
○Document has a valid `rel=canonical`

Send Feedback