jQuery undefined error HTML5 video tag addEventListener

Question

我有以下jquery代码

video1=$("#P div video"); alert(video1);
video1.addEventListener('ended',videoEnded,false);

并收到以下错误

TypeError：video1未定义

HTML

<div style="position: relative; z-index: 0;" id="P">
    <div style="position:absolute;left:0px;top:0px;z-index:0;">
        <video autoplay="" preload="auto">
            <source type="video/mp4" src="img/f.mp4"></source>
            <source type="video/ogg" src="img/f2.ogv"></source>
        </video>
    </div>
</div>