Edit in JSFiddle 

<!DOCTYPE html>

<html>
  <body style="margin:0;">
    <div id="player"></div>

    <script type="application/javascript">
      var tag = document.createElement('script');
      tag.src = "http://www.youtube.com/iframe_api";
      var firstScriptTag = document.getElementsByTagName('script')[0];
      firstScriptTag.parentNode.insertBefore(tag, firstScriptTag);

      var player;
      function onYouTubeIframeAPIReady() {
        var params = {
          width: '300',
          height: '200',
          videoId: 'UvEiSa6_EPA',
          playerVars: {
            'autoplay': 0,
            'controls': 0,
            'enablejsapi': 1,
            'playsinline': 1,
            'showinfo': 0
          },
          events: {
            'onReady': onPlayerReady
          }
        };
        player = new YT.Player('player', params);
      }

      function onPlayerReady(event) {
        event.target.playVideo();
      }
      </script>
  </body>
</html>