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 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:31.443 source:map[type:text value:[unattributed]]]]

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
li > div.evento > figure > img `li > div.evento > figure > img`	eventos.ucm.es/_files/_event/_152868/_header_img/_229233.png	397.5 KiB	393.9 KiB
Competiciones deportivas `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/competiciones/?ver=	495.1 KiB	392.4 KiB
li > div.evento > figure > img `li > div.evento > figure > img`	eventos.ucm.es/_files/_event/_152137/_header_img/_228735.png	393.0 KiB	389.3 KiB
li > div.evento > figure > img `li > div.evento > figure > img`	eventos.ucm.es/_files/_event/_152798/_header_img/_229128.png	250.8 KiB	247.9 KiB
¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 años … `article.item > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/concurso-primavera-matematicas-2026/?ver=n	288.1 KiB	233.6 KiB
li > div.evento > figure > img `li > div.evento > figure > img`	eventos.ucm.es/_files/_event/_152086/_header_img/_228385.jpe	192.9 KiB	189.7 KiB
li > div.evento > figure > img `li > div.evento > figure > img`	eventos.ucm.es/_files/_event/_149996/_header_img/_224396.png	127.5 KiB	124.5 KiB
Complutense Saludable `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/download/?ver=m	75.2 KiB	67.9 KiB
HR Excellence in Research `ul > li > a > img`	ucm.es/themes/ucm24/media/img/hrs4r.png	57.0 KiB	56.9 KiB
Deporte UCM `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/deporte-2/?ver=m	61.6 KiB	53.7 KiB
¡Inscríbete! `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/jornadas-para-familias-2026-pequena/?ver=m	50.4 KiB	42.0 KiB
Unidad de Cultura Científica UCM `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/foto-portada-ucm-259-x-175-px/?ver=m	46.2 KiB	38.8 KiB
Consulta de resultados provisionales `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/elecciones-claustro26/?ver=m	46.9 KiB	38.4 KiB
Cultura Complutense `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/osucm-navidad23-006/?ver=m	44.7 KiB	36.8 KiB
Fundación Complutense `article > figure.n_img > a > img`	/ext/apps/file/news/imagen-página-web-miniatura-ucmweb-...	42.3 KiB	34.9 KiB
Investigación UCM `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/investigacion/?ver=m	40.7 KiB	32.7 KiB
Prevención de Riesgos Laborales `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/web-bn-pq-prl-01-262x200/?ver=m	38.7 KiB	30.3 KiB
Elecciones 2026: procesos en curso `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/2claustro-universitario26/?ver=m	34.1 KiB	25.5 KiB
Logo `div.didomi-popup-container > div.didomi-popup-view > div.didomi-popup-notice-logo-container > img.didomi-popup-notice-logo`	www.ucm.es/themes/ucm16/media/img/logo.png	21.8 KiB	20.1 KiB
UCM Directo `section#eventos > header > a > img`	ucm.es/themes/ucm24/media/img/ucm-directo.png	13.3 KiB	12.9 KiB
Universidades Españolas con Ucrania `ul > li > a > img`	ucm.es/themes/ucm24/media/img/ucrania.png	6.7 KiB	6.5 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-4-IMG

nodeLabel: ¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 años …

path: 1,HTML,1,BODY,4,MAIN,0,DIV,0,SECTION,0,DIV,0,DIV,1,ARTICLE,0,FIGURE,0,A,0,IMG

selector: article.item > figure.n_img > a > img

snippet: <img src="https://www.ucm.es/ext/apps/file/news/concurso-primavera-matematicas-2026/…" alt="¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 …" loading="lazy">

HTTP/2 and HTTP/3 offer many benefits over HTTP/1.1, such as multiplexing. Learn more about using modern HTTP.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Protocol
ucm.es/	http/1.1
ucm.es/themes/ucm24/css/bootstrap.css	http/1.1
ucm.es/themes/ucm24/css/font-awesome.min.css	http/1.1
ucm.es/themes/ucm24/css/ucm-theme.css?ft=20260421140505	http/1.1
ucm.es/themes/ucm24/css/ucm.css?ft=20260421140505	http/1.1
ucm.es/themes/ucm24/css/ucm-wg.css?ft=20260421140505	http/1.1
ucm.es/themes/ucm24/css/ucm_home.css?ft=20260421140505	http/1.1
ucm.es/themes/ucm24/css/menu_3.css?ft=20260421140504	http/1.1
ucm.es/themes/ucm24/media/img/logo.svg	http/1.1
ucm.es/themes/ucm24/media/img/banderas/en.png	http/1.1
ucm.es/themes/ucm24/media/img/youtube.svg	http/1.1
ucm.es/themes/ucm24/media/img/facebook.svg	http/1.1
ucm.es/themes/ucm24/media/img/x.svg	http/1.1
ucm.es/themes/ucm24/media/img/linkedin.svg	http/1.1
ucm.es/themes/ucm24/media/img/instagram.svg	http/1.1
ucm.es/themes/ucm24/media/img/tiktok.svg	http/1.1
ucm.es/themes/ucm24/media/img/bluesky.svg	http/1.1
ucm.es/themes/ucm24/media/img/hrs4r.png	http/1.1
ucm.es/themes/ucm24/media/img/una-europa.svg	http/1.1
ucm.es/themes/ucm24/media/img/ucrania.png	http/1.1
ucm.es/themes/ucm24/js/jquery.min.js	http/1.1
ucm.es/themes/ucm24/js/bootstrap.js	http/1.1
ucm.es/themes/ucm24/js/ucm.js?ft=20260421140505	http/1.1
ucm.es/themes/ucm24/js/ucm_carousel.js?ft=20260421140505	http/1.1
ucm.es/themes/ucm24/css/print.css?ft=20260421140505	http/1.1
ucm.es/themes/ucm24/fonts/Roboto-Regular.ttf	http/1.1
ucm.es/themes/ucm24/fonts/fontawesome-webfont.woff2?v=4.7.0	http/1.1
www.ucm.es/ext/apps/file/news/concurso-primavera-matematicas-2026/?ver=n	http/1.1
www.ucm.es/ext/apps/file/news/jornadas-para-familias-2026-pequena/?ver=m	http/1.1
www.ucm.es/ext/apps/file/news/web-bn-pq-prl-01-262x200/?ver=m	http/1.1
www.ucm.es/ext/apps/file/news/2claustro-universitario26/?ver=m	http/1.1
www.ucm.es/ext/apps/file/news/elecciones-claustro26/?ver=m	http/1.1
ucm.es/themes/ucm24/media/img/ucm-tribuna-complutense.svg	http/1.1
ucm.es/themes/ucm24/media/img/ucm-directo.png	http/1.1
www.ucm.es/ext/apps/file/news/osucm-navidad23-006/?ver=m	http/1.1
www.ucm.es/ext/apps/file/news/investigacion/?ver=m	http/1.1
www.ucm.es/ext/apps/file/news/deporte-2/?ver=m	http/1.1
ucm.es/themes/ucm24/media/img/iconos/ucm-informacion.svg	http/1.1
ucm.es/themes/ucm24/media/img/iconos/ucm-transparencia.svg	http/1.1
ucm.es/themes/ucm24/media/img/iconos/ucm-sede-electronica.svg	http/1.1
ucm.es/themes/ucm24/media/img/iconos/ucm-becas-y-ayudas.svg	http/1.1
ucm.es/themes/ucm24/media/img/iconos/ucm-perfil-del-contratante.svg	http/1.1
ucm.es/themes/ucm24/media/img/iconos/ucm-biblioteca.svg	http/1.1
ucm.es/themes/ucm24/media/img/iconos/ucm-campus-virtual.svg	http/1.1
ucm.es/themes/ucm24/media/img/iconos/ucm-online.svg	http/1.1
www.ucm.es/ext/apps/file/news/competiciones/?ver=	http/1.1
www.ucm.es/ext/apps/file/news/foto-portada-ucm-259-x-175-px/?ver=m	http/1.1
www.ucm.es/ext/apps/file/news/download/?ver=m	http/1.1
/ext/apps/file/news/imagen-página-web-miniatura-ucmweb-...	http/1.1
www.ucm.es/themes/ucm16/media/img/logo.png	http/1.1
ucm.es/themes/ucm24/media/img/logoucm.ico	http/1.1

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.

URL	Transfer Size	Duration
ucm.es/themes/ucm24/css/menu_3.css?ft=20260421140504	2.0 KiB
ucm.es/themes/ucm24/css/ucm_home.css?ft=20260421140505	5.8 KiB	133 ms
ucm.es/themes/ucm24/css/ucm-wg.css?ft=20260421140505	12.0 KiB	175 ms
ucm.es/themes/ucm24/css/ucm.css?ft=20260421140505	6.7 KiB	133 ms
ucm.es/themes/ucm24/css/font-awesome.min.css	9.3 KiB	175 ms
ucm.es/themes/ucm24/css/ucm-theme.css?ft=20260421140505	2.2 KiB	133 ms
ucm.es/themes/ucm24/css/bootstrap.css	32.7 KiB	175 ms

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
/dc628592-8975-46a5-82c3-2fb34d165e56/loader.js?target=uc...	7200.0 s	29.7 KiB

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
ucm.es/themes/ucm24/fonts/Roboto-Regular.ttf	20 ms
ucm.es/themes/ucm24/fonts/fontawesome-webfont.woff2?v=4.7.0	10 ms

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

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: 40 ms 7.3 KiB

URL	Transfer Size	Est Savings
ucm.es/themes/ucm24/js/bootstrap.js	21.3 KiB	7.3 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: 40 ms 56.2 KiB

URL	Transfer Size	Est Savings
ucm.es/themes/ucm24/css/bootstrap.css	32.2 KiB	30.3 KiB
	16.6 KiB	14.3 KiB
ucm.es/themes/ucm24/css/ucm-wg.css?ft=20260421140505	11.5 KiB	11.5 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: 40 ms 209.0 KiB

URL	Transfer Size	Est Savings
www.googletagmanager.com/gtag/js?id=G-65GWBF2XN6&cx=c&gtm=4e64h1	155.5 KiB	66.9 KiB
www.googletagmanager.com/gtag/js?id=G-6XY0QFTRLR	157.7 KiB	63.5 KiB
/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/sdk....	101.3 KiB	54.5 KiB
ucm.es/themes/ucm24/js/jquery.min.js	40.4 KiB	24.1 KiB

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
Pages with cache-control:no-store header cannot enter back/forward cache.	Actionable
Pages whose main resource has cache-control:no-store cannot enter back/forward cache.	Not actionable
Back/forward cache is disabled because some JavaScript network request received resource with Cache-Control: no-store header.	Not 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 7.9 KiB

URL	Transfer Size	Est Savings
ucm.es/themes/ucm24/css/bootstrap.css	32.7 KiB	5.5 KiB
ucm.es/themes/ucm24/css/ucm-wg.css?ft=20260421140505	12.0 KiB	2.5 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.

URL	Transfer Size
www.ucm.es/ext/apps/file/news/competiciones/?ver=	495.4 KiB
eventos.ucm.es/_files/_event/_152868/_header_img/_229233.png	398.2 KiB
eventos.ucm.es/_files/_event/_152137/_header_img/_228735.png	393.7 KiB
eventos.ucm.es/_files/_event/_152899/_header_img/_229286.png	386.9 KiB
www.ucm.es/ext/apps/file/news/concurso-primavera-matematicas-2026/?ver=n	288.4 KiB
eventos.ucm.es/_files/_event/_152798/_header_img/_229128.png	251.3 KiB
eventos.ucm.es/_files/_event/_152086/_header_img/_228385.jpe	193.3 KiB
eventos.ucm.es/_files/_event/_152877/_header_img/_229278.jpe	182.3 KiB
eventos.ucm.es/_files/_event/_152873/_header_img/_229280.jpe	182.3 KiB
www.googletagmanager.com/gtag/js?id=G-6XY0QFTRLR	158.0 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
HR Excellence in Research `ul > li > a > img`	ucm.es/themes/ucm24/media/img/hrs4r.png
Competiciones deportivas `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/competiciones/?ver=
ul.di_bloque1 > li > a > img `ul.di_bloque1 > li > a > img`	ucm.es/themes/ucm24/media/img/iconos/ucm-informacion.svg
ul.di_bloque1 > li > a > img `ul.di_bloque1 > li > a > img`	ucm.es/themes/ucm24/media/img/iconos/ucm-transparencia.svg
ul.di_bloque1 > li > a > img `ul.di_bloque1 > li > a > img`	ucm.es/themes/ucm24/media/img/iconos/ucm-sede-electronica.svg
ul.di_bloque1 > li > a > img `ul.di_bloque1 > li > a > img`	ucm.es/themes/ucm24/media/img/iconos/ucm-becas-y-ayudas.svg
ul.di_bloque1 > li > a > img `ul.di_bloque1 > li > a > img`	ucm.es/themes/ucm24/media/img/iconos/ucm-perfil-del-contratante.svg
ul.di_bloque1 > li > a > img `ul.di_bloque1 > li > a > img`	ucm.es/themes/ucm24/media/img/iconos/ucm-biblioteca.svg
ul.di_bloque2 > li > a > img `ul.di_bloque2 > li > a > img`	ucm.es/themes/ucm24/media/img/iconos/ucm-campus-virtual.svg
ul.di_bloque2 > li > a > img `ul.di_bloque2 > li > a > img`	ucm.es/themes/ucm24/media/img/iconos/ucm-online.svg
Fundación Complutense `article > figure.n_img > a > img`	/ext/apps/file/news/imagen-página-web-miniatura-ucmweb-...
Complutense Saludable `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/download/?ver=m
Investigación UCM `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/investigacion/?ver=m
Cultura Complutense `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/osucm-navidad23-006/?ver=m
Deporte UCM `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/deporte-2/?ver=m
Unidad de Cultura Científica UCM `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/foto-portada-ucm-259-x-175-px/?ver=m
Universidad Complutense de Madrid `div#cabecera > div#logo > a > img`	ucm.es/themes/ucm24/media/img/logo.svg
Logo `div.didomi-popup-container > div.didomi-popup-view > div.didomi-popup-notice-logo-container > img.didomi-popup-notice-logo`	www.ucm.es/themes/ucm16/media/img/logo.png
Una Europa `ul > li > a > img`	ucm.es/themes/ucm24/media/img/una-europa.svg
Universidades Españolas con Ucrania `ul > li > a > img`	ucm.es/themes/ucm24/media/img/ucrania.png
Tribuna Complutense `ul.enlaces-noticias > li > a > img`	ucm.es/themes/ucm24/media/img/ucm-tribuna-complutense.svg

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

●Time to Interactive 1.8 s

●Layout shift culprits

●Document request latency

●Optimize DOM size

●LCP breakdown

●Optimize viewport for mobile

●Max Potential First Input Delay 40 ms

●User Timing marks and measures 13 user timings

●JavaScript execution time 0.1 s

●Minimizes main-thread work 0.4 s

●Network Requests

●Network Round Trip Times 20 ms

●Server Backend Latencies 130 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Avoid multiple page redirects

●Initial server response time was short Root document took 110 ms

●Avoid large layout shifts 4 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.

ARIA

Some ARIA parent roles must contain specific child roles to perform their intended accessibility functions. Learn more about roles and required children elements.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 años … `div.news-flex > section#zona_1_3 > div#carouselUcm > div.carousel-inner`

When an input field doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn more about input field labels.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 años … `div.news-flex > section#zona_1_3 > div#carouselUcm > div.carousel-inner`

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.

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
¡Un sábado de matemáticas y talento! Casi 4.000 jóvenes -de entre 10 y 17 años … `div.carousel-inner > article.item > div.news1_txt > h3`

These are opportunities to improve keyboard navigation in your application.

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
Defensora Universitaria `li > ul > li > a`
Inspección de Servicios `li > ul > 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]`s are contained by their required parent element

●`[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.

●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

●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 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

●`[lang]` attributes have a valid value

●Document has a main landmark.

●Deprecated ARIA roles were not used

●All heading elements contain content.

●Uses ARIA roles only on compatible elements

●Identical links have the same purpose.

●Elements with visible text labels have matching accessible names.

○`[accesskey]` values are unique

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

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○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

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

○`<object>` elements have alternate text

○Select elements have associated label elements.

○Skip links are focusable.

○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.

○`<video>` elements contain a `<track>` element with `[kind="captions"]`

○Tables have different content in the summary attribute and `<caption>`.

○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 display dimensions should match natural aspect ratio. Learn more about image aspect ratio.

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Aspect Ratio (Displayed)	Aspect Ratio (Actual)
English `ul#lg_items > li > a > img`	ucm.es/themes/ucm24/media/img/banderas/en.png	20 x 20 (1.00)	30 x 20 (1.50)

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
Investigación UCM `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/investigacion/?ver=m	436 x 238	300 x 164	436 x 238
Deporte UCM `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/deporte-2/?ver=m	436 x 237	300 x 163	436 x 237
Cultura Complutense `article > figure.n_img > a > img`	www.ucm.es/ext/apps/file/news/osucm-navidad23-006/?ver=m	436 x 237	300 x 163	436 x 237

●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

●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 clickjacking with XFO or CSP

●Mitigate DOM-based XSS with Trusted Types

●Detected JavaScript libraries

●Page has valid source maps

○Redirects HTTP traffic to HTTPS

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
main#portada > div.news-plus > section#eventos > a.ev-left `main#portada > div.news-plus > section#eventos > a.ev-left`
main#portada > div.news-plus > section#eventos > a.ev-right `main#portada > div.news-plus > section#eventos > a.ev-right`

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

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

○robots.txt is valid

○Document has a valid `rel=canonical`