RTCSessionDescription: type property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2017.

The property RTCSessionDescription.type is a read-only string value which describes the description's type.

Value

The possible values are:

"answer"

The SDP contained in the sdp property is the definitive choice in the exchange. In other words, this session description describes the agreed-upon configuration, and is being sent to finalize negotiation.

"offer"

The session description object describes the initial proposal in an offer/answer exchange. The session negotiation process begins with an offer being sent from the caller to the callee.

"pranswer"

The session description object describes a provisional answer; that is, a response to a previous offer that is not the final answer. It is usually employed by legacy hardware.

"rollback"

This special type with an empty session description is used to roll back to the previous stable state.

Example

js
// The remote description has been set previously on pc, a RTCPeerConnection
alert(pc.remoteDescription.type);

Specifications

Specification
WebRTC: Real-Time Communication in Browsers
# dom-rtcsessiondescription-type

Browser compatibility

See also