<html>
<body>
<video id="myVideo" width="320" height="240" poster="w3javascript.gif" controls>
<source src="movie.mp4" type="video/mp4">
<source src="movie.ogg" type="video/ogg">
您的浏览器不支持 video 标签。
</source></source></video>
<p>点击按钮修改预览图片。</p>
<button onclick="myFunction()">点我</button>
<script>
function myFunction()
{
document.getElementById("myVideo").poster="/static/images/ziqiangxuetang.png";
}
</script>
</body>
</html>