This feature is not on a current W3C standards track, but it is supported on the Firefox OS platform. Although implementations may change in the future and it is not supported widely across browsers, it is suitable for use in code dedicated to Firefox OS apps.
timeSeconds is a read-only property representing the time in seconds to wait before a call is forwarded.
var time = instanceOfMozMobileCFInfo.timeSeconds;
Returns a number indicating how many seconds the device will wait before forwarding an incoming call.
Tech reviewer question: Is this non-zero if call forwarding is disabled?
Not part of any specification.