Do not autoplay audio without a way to stop it
Sound starts on its own when the page loads and there is no way to stop it. F93 is the failure technique for that, and a match is a defect rather than a technique. Five things have to be true at once before it applies, which is where most arguments about it finish. There has to be an audio track, it has to run longer than three seconds, the element has to carry autoplay, it must not carry muted, and there must be no control offered to pause or stop it. So the muted background video every marketing site ships does not fail here. A silent loop sits outside the technique entirely. One more exit exists and it is a wide one. Where the browser gives the user a preference that overrides autoplay, the failure does not occur, and every current browser blocks unmuted autoplay by default.
How we find it in an audit
We load each audited page in a quiet room and listen, which sounds crude and is the only test that settles anything. Where sound starts, we work through the five conditions in order. Audio track, longer than three seconds, autoplay present, muted absent, no way offered to stop it. The markup gets read alongside, because a script calling play is a different and worse case than the autoplay attribute, which a browser preference can override. A control that stops the sound counts, and so does an independent volume control that reaches zero.
How affected users experience it
A screen reader speaks, and the page speaks, in the same ears at the same volume. Nothing can be understood while both are running. And the user cannot go and find the stop button, because finding it means listening to the screen reader read the page they cannot hear. That is the trap in one sentence. The only reliable escape is closing the tab, which is what most people do, and the site never learns why they left.
Passes vs. fails
Passes
<audio src="theme.mp3" controls></audio> <!-- sound starts only when the user asks for it -->Fails
<audio src="theme.mp3" autoplay></audio>How this gets tested
The W3C publishes test rules that define what a checker looks for here.
- Audio or video element avoids automatically playing audioA tool can check this
- Audio or video element that plays automatically has a control mechanismA tool can check this
- Audio or video element that plays automatically has no audio that lasts more than 3 secondsA tool can check this
The other techniques filed under this rule
5 guides on this site are filed under 1.4.2 Audio Control. W3C documents this one as a failure of that rule, so it describes a way the rule gets broken rather than a way to pass it.
This guide is our interpretation of W3C technique F93: Failure of Success Criterion 1.4.2 for absence of a way to pause or stop an HTML5 media element that autoplays. W3C publishes its techniques as guidance rather than as the standard, and says so on every one of them. The success criterion is what conformance is measured against, and a technique is one documented way to meet it.