x
 
<!DOCTYPE html> 
<html> 
<body> 
<p>本例使用 HTML DOM 将 "ondurationchange" 事件分配给 video 元素。</p>
<video controls id="myVideo">
  <source src="/i/photo/shanghai.mp4" type="video/mp4">
  Your browser does not support HTML5 video.
</video>
<script>
document.getElementById("myVideo").ondurationchange = function() {myFunction()};
function myFunction() {
  alert("The video duration has changed");
}
</script>
</body> 
</html>