This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
serviceClass is a read-only property that represents the service for which the call forward is set up.
var service = instanceOfMozMobileCFInfo.serviceClass;
Return a number.
The value is equal to one of the
MozMobileConnection.ICC_SERVICE_CLASS_* constant values.
Not part of any specification.