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.
action is a read-only property that indicates what to do with the call forwarding rule.
var action = instanceOfMozMobileCFInfo.action;
Returns a number, whose value is one of the
MozMobileCFInfo.CALL_FORWARD_ACTION_* constant values.
Not part of any specification.