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.
mcc is a read-only property that represents the Mobile Country Code (MCC) of the network operator.
var mcc = navigator.mozMobileConnection.data.network.mcc
Return a string.
Not part of any specification.