javascript for webrtc webcam stream

stream.js

window.onload = function() {

  var video = document.querySelector('video');
	var canvas = document.querySelector('canvas');
	var ctx = canvas.getContext('2d');
	var localMediaStream = null;

	window.URL = window.URL || window.webkitURL;
	navigator.getUserMedia  = navigator.getUserMedia || navigator.webkitGetUserMedia ||
	                          navigator.mozGetUserMedia || navigator.msGetUserMedia;

  /* creates the stream if user allows webcam to start */
  navigator.getUserMedia({video: true}, function(stream) {
	  video.src = window.URL.createObjectURL(stream);
	  localMediaStream = stream;
	}, onFail);

}