在线运行代码 - 菜鸟教程

<!DOCTYPE html> 
<html> 
<head> 
<meta charset="utf-8"> 
<title>菜鸟教程(cainiaoplay.com)</title>
</head>
<body> 

<button onclick="enablePreload()" type="button">加载视频</button>
<button onclick="disablePreload()" type="button">不加载视频</button>
<button onclick="checkPreload()" type="button">检查加载状态</button>
<br> 
<video id="video1" controls="controls">
  <source src="mov_bbb.mp4.html" type="video/mp4">
  <source src="mov_bbb.ogg.html" type="video/ogg">
  您的浏览器不支持 HTML5 video  标签。
</video>

<script>
myVid=document.getElementById("video1");
function enablePreload()
{ 
  myVid.preload="auto";
}  
function disablePreload()
{ 
  myVid.preload="none";
} 
function checkPreload()
{ 
  alert(myVid.preload);
} 
</script> 

<p>Video courtesy of <a href="http://www.bigbuckbunny.org/" target="_blank">Big Buck Bunny</a>.</p>

</body> 
</html>
源代码

动行结果
