Features

A list of every a11y concern Checka11y.css will check for and highlight with links to relevant guidelines or techniques:

Errors

E0000: Checks for invalid interactive HTML elements elements nested inside of a <button>.
E0001: Checks that every <button> has meaningful content.
E0002: Checks that all instances of the dir attribute is only set to ltr, rtl or auto.
E0003: Checks that headings are not empty.
E0004: Checks that headings are reachable by assistive technologies.
E0005: Checks headings are in a semantic order.
E0006: Checks that the lang attribute exists on the <html> element and that is is not empty.
E0007: Checks for missing title attribute on <iframe> elements.
E0008: Checks for missing alt attributes on images.
E0009: Checks for invalid interactive HTML elements elements nested inside of an <a>.
E0010: Checks that every <a> has meaningful content.
E0011: Checks <li>, <script> and <template> are the only direct children of <ol> and <ul>.
E0012: Checks <dt> and <dd> are the only direct children of <dl>.
E0013: Checks if <nav> exists more than once on a page, that each nav is correctly labelled.
E0014: Checks for a tab index value of -1 on commonly tabbed to elements.
E0015: Checks for an image with a longdesc pointing to an image.
E0016: Checks for an image with an empty longdesc.
E0017: Checks for an empty <title> in the <head>.
E0018: Checks for an <head> without a <title> element inside.

W0000: Checks for the use of accesskey and warns due to accessibility, internationalisation and browser support concerns.
W0001: Checks to see if any <video> and <audio> elements have the autoplay attribute set.
W0002: Checks and warns about using mouse event handlers on HTML elements that are potentially not reachable from the keyboard.
W0003: Checks that alt attributes on images have meaningful content.
W0004: Checks for !important inline styles thay may override end-user's custom stylesheets.
W0005: Checks for <span> and <em> elements that could potentially break up spoken text.
W0006: Checks for <a target="_blank"> and warns about links that open in a new window.
W0007: Checks for <u> being confused as hyperlinks.
W0008: Checks for the use of the title attribute due to accessibility concerns.
W0009: Checks for focusable elements inside aria-hidden="true" elements.
W0010: Checks for heading elements containing role="text" attribute.
W0011: Checks for anchor tags that are used as buttons.
W0012: Checks for heading element inside <section> element.
W0013: Checks for anchor tags that contain a link to a PDF, Word, Excel, or PowerPoint document.
W0014: Checks for anchor tags that contain a link to content site.
W0015: Checks for images with the longdesc attribute.
W0016: Checks for zoom/scale being disabled in the meta viewport.