1、要引入的視訊

<iframe height=498 width=510 src="http://player.youku.com/embed/XMTI4MjU5OTA3Mg==" frameborder=0 allowfullscreen></iframe>

2、css裡設定iframe的寬度為100%

3、根據螢幕寬度自適應，這裡我設定視訊16/9的固定比例

window.onload = window.onresize = function () {
    resizeIframe();
}
var resizeIframe=function(){
    var bodyw=document.body.clientWidth;
    for
 
(var ilength=0;ilength<=document.getElementsByTagName("iframe").length;ilength++){

        document.getElementsByTagName("iframe")[ilength].height = bodyw*9/16;//設定高度

    }
}