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 property RTCPeerConnection.localDescription returns an RTCSessionDescription describing the session for the local end of the connection. If it has not yet been set, this is null.


var sessionDescription = peerConnection.localDescription;

On a more fundamental level, the returned value is the value of RTCPeerConnection.pendingLocalDescription if that property isn't null; otherwise, the value of RTCPeerConnection.currentLocalDescription is returned. See "Pending and current descriptions" in WebRTC connectivity for details on this algorithm and why it's used.


This example looks at the localDescription and displays an alert containing the RTCSessionDescription object's type and sdp fields.

var pc = new RTCPeerConnection();
var sd = pc.localDescription;
if (sd) {
  alert("Local session: type='" +         
        sd.type + "'; sdp description='" +
        sd.sdp + "'");
else {
  alert("No local session yet.");


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

Browser compatibility

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

[1] Though this property is not prefixed, the interface it belongs to is, until Firefox 44.

See also


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

Experimental Expérimental localDescription Property Read-only Reference Référence RTCPeerConnection WebRTC