The volumeControlChannel property of the AudioChannelManager interface returns a DOMString that allows you to set which audio channel should have its volume changed when you press the device's hardware volume controls.
Syntax
var myVolumeControlChannelValue = navigator.mozAudioChannelManager.volumeControlChannel; navigator.mozAudioChannelManager.volumeControlChannel = 'content';
Value
A Boolean value
Example
In the following simple example, we use the navigator.mozAudioChannelManager property to access the app's AudioChannelManager object, first to do some rudimentary feature detection, and then to set value of the AudioChannelManager.volumeControlChannel property, based on a received variable.
var channelValue = 'content';
if (navigator.mozAudioChannelManager) {
if(channelValue == 'normal') {
navigator.mozAudioChannelManager.volumeControlChannel = 'normal';
} else if(channelValue == 'content') {
navigator.mozAudioChannelManager.volumeControlChannel = 'content';
}
console.log(navigator.mozAudioChannelManager.volumeControlChannel);
}
Note: For a complete working example, see our audio-channels-demo. Try running this on your Firefox OS device as an installed app (install it using App Manager/WebIDE) and then see what happens when you play the music and then put the app in the background, with the channel set to normal, then content.
Specifications
The AudioChannels API has no official spec at the moment; see https://wiki.mozilla.org/WebAPI/AudioChannels for implementation details, WebIDL, etc.