Using MediaStream API

Using the MediaStream API to access webcam from JavaScript:

navigator.webkitGetUserMedia("video,audio", 
  function(stream) {
    var url = webkitURL.createObjectURL(stream);
    videoTag.src = url;
    videoTag.onerror = function() {
      stream.stop();
      alert('camera error');
    };
  },
  function(error) {
    alert(error.code);
  }
);