The Idle API is used to notify an app when the user is idle. This lets an app take action when the user is doing nothing with his device. The most common use case is to save battery power; in this case, it is commonly used in conjuction with the Power Management API.
Returns the code of the currently active language.
Returns the direction of the currently active language (ltr or rtl).
readyState should be used sparingly;  L10n.ready() and L10n.once() are usually better suited for controlling when code is run relative to the state of the localization.
The MozActivity interface allows apps to delegate an activity to another app.
The add method is used to retrieve a list of pending alarms.
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.
The MozContact interface is used to describe a single contact in the device's contact database.
The additionalName property is a list of any additional names (other than given names or family names) usable for the contact.
The anniversary property represents the anniversary date of the contact (which can be different than its birthday date).
The bday property represents the birthday date of the contact.
The category property is a list of all the different categories the contact is associated with.
The email property is a list of all the possible e-mails for the contact.
The genderIdentity property represents the actual gender identity of the contact (which can be different than its actual sex).