The navigator.mozAudioChannelManager object provides access to the mozAudioChannelManager interface, which is used to manage your Firefox OS device's audio channels, including setting what channel's volume to affect when the volume buttons are pressed inside a particular app.
Syntax
var mgr = window.navigator.mozAudioChannelManager;
Return value
A mozAudioChannelManager object.
Specifications
The AudioChannels API has no official spec at the moment; see https://wiki.mozilla.org/WebAPI/AudioChannels for implementation details, WebIDL, etc.