If there is audio on a web page that plays automatically for more than three seconds, you must provide the user with a mechanism to control the volume of the audio, to pause it or turn it off. This is especially important for users of screen readers, since the sound of the audio file can drown out the sound of the screen reader. Be aware that having a sound play automatically on page load may interfere with a screen reader user's ability to find the sound's controls, so having a sound play automatically, rather than at the user's command is discouraged.
Official Requirements:
1.4.2 Audio Control: 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.
Note: Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether or not it is used to meet other success criteria) must meet this success criterion. See Conformance Requirement 5: Non-Interference.
How to fix:
- Carefully consider whether it's necessary to play a sound automatically on page load at all. Even users who aren't using assistive technology may find it annoying.
- Configure the page so that the sound plays upon user request, not automatically.
- If you don't want to provide controls for the sound, make sure it lasts less than 3 seconds.
- If the audio is longer than three seconds, you must provide easily accessibly controls to stop it, to pause it, and to control its volume independently of the system volume control , as screen readers are also controlled by the system volume control.
