playbackRate控制音频播放倍速

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>
<body>
  
  <button onclick="accelerate()">加速</button>
  <button onclick="playVideo()">播放</button>
  <button onclick="slow()">减速</button>
  <script>
    var src = 'https://m801.music.126.net/20190516150553/1e0321bcf7046f8052a43eedc978e33a/jdyyaac/005f/0f5b/030b/751fc2b41b81fa17dac24a81e2934c2f.m4a';  
    
    var myVid=document.createElement('audio');
    console.log(myVid)
    myVid.autoplay = true;
    myVid.src = src;
    myVid.playbackRate=0.5;
    function accelerate(){
      myVid.playbackRate = myVid.playbackRate + 0.1
      console.log(myVid.playbackRate)
    }
    
    function slow() {
      myVid.playbackRate = myVid.playbackRate - 0.1
      console.log(myVid.playbackRate)
    }

    function playVideo() {
      myVid.play();
    }
  </script>
</body>
</html>