video去播放控件

<video id="myVideo" width="320" height="240">
<source src="movie.mp4" type="video/mp4">
<source src="movie.ogg" type="video/ogg">
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</source></source></video><br>
<button onclick="enableControls()" type="button">启用控件</button>
<button onclick="disableControls()" type="button">禁用控件</button>
<button onclick="checkControls()" type="button">查看控件状态</button>
<script>
var x = document.getElementById("myVideo");
function enableControls()
  { 
  x.controls = true;
  x.load();
  } 
function disableControls()
  { 
  x.controls = false;
  x.load();
  } 
function checkControls()
  { 
  alert(x.controls);
  }