This API is available on Firefox OS for internal applications only.
Summary
The settingName property of the MozSettingsEvent specifies the exact name of the setting that has changed. For an up-to-date list of possible setting names, take a look at the Gaia source code.
Syntax
var name = instanceOfMozSettingsEvent.settingName;
Value
A string indicating the name of the changed setting.
Specification
Not part of any specification yet; however, this API will be discussed at W3C as part of the System Applications Working Group.