api - onPlayerStateChange YouTube API が機能しない

Question

次のAPIは機能しません。この問題を解決するにはどうすればよいですか?

<div id="player"></div>
<script src="http://www.youtube.com/player_api"></script>
<script>
    // Create YouTube player
    var player;
    function onYouTubePlayerAPIReady() {
        player = new YT.Player('player', {
          height: '390',
          width: '640',
          videoId: '0Bmhjf0rKe8',
          events: {
            'onReady': onPlayerReady,
            'onStateChange': onPlayerStateChange
          }
        });
    }

    // Autoplay video
    function onPlayerReady(event) {
        event.target.playVideo();
    }

    // When video ends
    function onPlayerStateChange(event) {
        if(event.data === 0) {
            alert('done');
        }
    }
</script>