javaScript随机图片

<script type="text/javascript">
    //<!CDATA[
    var pic = [];
    pic[0] = "链接";
    pic[1] = "链接";
    pic[2] = "链接";
    pic[3] = "链接";

    var randomBgIndex = Math.round( Math.random() * 3 );

    //输出随机的背景图
    //document.write('<style>body{background:url(' + bodyBgs[randomBgIndex] + ') no-repeat 50% 0}</style>');
    document.write("<img src=" + pic[randomBgIndex] + " width='400'>")
    //]]>
</script>