<button onclick="getNWState()" type="button">获得网络状态</button>
<video id="video1" controls="controls" autoplay="autoplay">
<source src="/example/html5/mov_bbb.mp4" type="video/mp4">
<source src="/example/html5/mov_bbb.ogg" type="video/ogg">
Your browser does not support HTML5 video.
myVid=document.getElementById("video1");
alert(myVid.networkState);