What the standard says
If any audio on a web page plays automatically for more than 3 seconds, either a mechanism is available to pause or stop the audio, or a mechanism is available to control audio volume independently from the overall system volume level.
Why it matters
Autoplaying audio drowns out a screen reader, which is also speech. The user cannot hear their own software to find the stop button.
What a failure looks like
- failsA background video with sound that starts on load.
- failsAn audio ad with no visible control.
How to fix it
- doDo not autoplay audio. If you must, start muted and put a pause control first in the tab order.
How A11ySignal checks it
1 automated check runs against this criterion on every scan.
moderateno-autoplay-audio<video> or <audio> elements must not play automatically