gistfile1.html

<template name='video'>
  <p align="center"><input type="button" id="share_screen" value="Share screen"/></p>
  <p align="center"><video id="video" autoplay='autoplay'></video></p>

  <script language="javascript">
    navigator.getUserMedia = navigator.webkitGetUserMedia || navigator.getUserMedia;
    $('#share_screen').click(function() {
          navigator.getUserMedia({
                  audio: false,
                  video: {
                          mandatory: {
                          chromeMediaSource: 'screen',
                          maxWidth: 1280,
                          maxHeight: 720
                      },
                      optional: []
                  }
              }, function(stream) {
                  document.getElementById('video').src = window.URL.createObjectURL(stream);;
                  $('#share_screen').hide();
              }, function(e) {
                  console.log(e);
                  alert('Error, my friend. Screen stream is not available. Try in latest Chrome with Screen sharing enabled in about:flags.');
                }
          )
    })
  </script>
</template>