function mute() {
		if (ytplayer) {
			ytplayer.mute();
            hideItem('player-mute');
			showItem('player-unmute');			
		}
	}

	function unMute() {
		if (ytplayer) {
            ytplayer.unMute();
            hideItem('player-unmute');
			showItem('player-mute');
          }
        }

        function play() {
          if (ytplayer) {
            ytplayer.playVideo();
			hideItem('player-play');
			showItem('player-pause');
          }
        }

        function pause() {
          if (ytplayer) {
            ytplayer.pauseVideo();
			hideItem('player-pause');
			showItem('player-play');
          }
          
        }

        function stop() {
          if (ytplayer) {
            ytplayer.stopVideo();
			hideItem('player-pause');
			showItem('player-play');            
          }
        }
        function loadNewVideo(id, startSeconds) {
          if (ytplayer) {
            ytplayer.loadVideoById(id, parseInt(startSeconds));
          }
        }
        function cueNewVideo(id, startSeconds) {
          if (ytplayer) {
            ytplayer.cueVideoById(id, startSeconds);
          }
        }


	function onYouTubePlayerReady(playerId) {
		ytplayer = document.getElementById("pupilsPlayer");
		ytplayer.cueVideoById(document.getElementById("video-id").value);
        }