var isReady=0;
      var player;
      function onYouTubeIframeAPIReady() {
        isReady=1;
      }

      // 4. The API will call this function when the video player is ready.
      function onPlayerReady(event) {
        event.target.playVideo();
      }

      // 5. The API calls this function when the player's state changes.
      //    The function indicates that when playing a video (state=1),
      //    the player should play for six seconds and then stop.
      var done = false;
      function onPlayerStateChange(event) {
        if (event.data == YT.PlayerState.PLAYING && !done) {
          setTimeout(stopVideo, 6000);
          done = true;
        }
      }
      function stopVideo() {
        player.stopVideo();
      }
      function onModalOpen(){
        if(isReady==1){
          player = new YT.Player('player', {
            height: '390',
            width: '640',
            videoId: 'u1zgFlCw8Aw',
            events: {
              'onReady': onPlayerReady,
              'onStateChange': onPlayerStateChange
            }
          });
        }
      }
      function onModalClose(){
        player=null;
      }