This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage 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 specification changes.

The read-only RTCDataChannel property protocol returns a DOMString containing the name of the subprotocol in use. If no protocol was specified when the data channel was created, then this property's value is "" (the empty string).

The permitted values of this property are defined by the Web site or app using the data channel.

The ability for each channel to have a defined subprotocol lets your app, for example, use JSON objects as messages on one channel while another channel is plaintext and another is raw binary or even some other format.


var subProtocol = aDataChannel.protocol;


A string identifying the app-defined subprotocol being used for exchanging data on the channel. If none has been established, this is an empty string ("").


var pc = new RTCPeerConnection();
var dc = pc.createDataChannel("my channel", {
           protocol: "json"

function handleChannelMessage(dataChannel, msg) {
  switch(dataChannel.protocol) {
    case "json":
      /* process JSON data */
    case "raw":
      /* process raw binary data */


Specification Status Comment
WebRTC 1.0: Real-time Communication Between Browser
The definition of 'RTCDataChannel.protocol' in that specification.
Working Draft Initial specification.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) 22 (22) [1] No support (Yes) ?
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support ? (Yes) 22.0 (22) [1] No support ? ?

[1] The interface is called DataChannel instead of the standard RTCDataChannel in Firefox; however, a binding has been in place since Firefox 24 which allows either name to be used.

See also


© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.

Experimental NeedsExample Property Protocol Read-only Reference RTCDataChannel WebRTC