This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for the proper prefixes to use in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the spec changes.
Example
var pc = new RTCPeerConnection();
var descriptionCallback = function(offer) {
pc.setLocalDescription(offer);
}
pc.createOffer(descriptionCallback);