This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

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


var value = sessionDescription.type;
sessionDescription.type = value; 


The possible values are defined by an enum of type RTCSdpType.

The allowed values are those of an enum of type RTCSdpType:

  • "offer", the description is the initial proposal in an offer/answer exchange.
  • "answer", the description is the definitive choice in an offer/answer exchange.
  • "pranswer", the description is a provisional answer and may be changed when the definitive choice will be given.
  • "rollback", the description rolls back to offer/answer state to the last stable state.


// The remote description has been set previously on pc, a RTCPeerconnection



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

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes15 Yes -moz- No ? ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes Yes ? ? ? Yes

See also

Document Tags and Contributors

Contributors to this page: fscholz, nils, abbycar, Sheppy, teoli
Last updated by: fscholz,