The MediaStream.id() read-only property is a DOMString containing 36 characters denoting a unique identifier (GUID) for the object. Syntax var id = mediaStream.id; Example var p = navigator.mediaDevices.getUserMedia({ audio: true, video: true }); p.then(function(stream) { console.log(stream.id); };) Specifications Specification Status Comment Media Capture and StreamsThe definition of 'MediaStream.id' in that specification. Editor's Draft Initial definition. Browser compatibility Desktop Mobile Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari Basic support ? (Yes) 41 (41) ? ? ? Feature Android Edge Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile Basic support ? (Yes) 41.0 (41) ? ? ? See Also MediaStream, the interface this property belongs to.