强制嵌入youtube视频静音和重播

Question

当我嵌入视频时，我没有成功访问youtube iframe api。

这是我的代码：

 <iframe id="player" width="560" height="315" src="//www.youtube.com/embed/xWPDujqIwZc?autoplay=1" frameborder="0" enablejsapi="1"></iframe>
    <script type="text/javascript" src="youtube.js"></script>

这是＃youtube.js

   var tag = document.createElement('script');
tag.src = "https://www.youtube.com/iframe_api";
var firstScriptTag = document.getElementsByTagName('script')[0];
firstScriptTag.parentNode.insertBefore(tag, firstScriptTag);

var player;
function onYouTubeIframeAPIReady() {
  player = new YT.Player('player', {
    events: {
      'onReady': onPlayerReady,
      'onStateChange': onPlayerStateChange
    }
  });
}

function onPlayerReady(event) 
{
    event.target.playVideo();
    player.mute();
}

function onPlayerStateChange(event) {
if (event.data == 0) 
    {
        event.target.playVideo();
    }
}

感谢您的帮助！