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.
spn is a read-only property representing the Service Provider Name (SPN) of the subscriber's home network.
var spn = navigator.mozMobileConnection.iccInfo.spn;
Return a string.
Not part of any specification.