This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

The RTCSessionDescriptionCallback type is used to represent the callback function passed into the deprecated callback-based version of createOffer() or createAnswer() when using them to create offers or answers.

Because this function type is part of the legacy WebRTC API, you should avoid using it (and the callback-based forms of createOffer() and createAnswer() that make use of it).




An RTCSessionDescriptionInit (or RTCSessionDescription) object describing the session being offered or being accepted. This object contains the type and sdp properties which are part of RTCSessionDescription.

Return value

The callback doesn't need to return anything, so the return value is undefined.


var pc = new RTCPeerConnection();
var descriptionCallback = function(offer) {


Specification Status Comment
WebRTC 1.0: Real-time Communication Between Browsers
The definition of 'RTCSessionDescriptionCallback' in that specification.
Candidate Recommendation Initial definition.

Browser compatibility

BCD tables only load in the browser

See also