用 JavaScript 控制网页的 CSS 代码的 link方式就ok了每次进入的时候 调用不同的 CSS 就可以实现不同的效果 方法一：
<link id="chun" type="text/css" rel="stylesheet" href="css/1.css">
<script Language="JavaScript"> <!--
Begin var Folder = "css/"; //
var how_many_ads = 4;
var now = new Date();
var sec = now.getSeconds();
var ad = sec % how_many_ads;
var css = "";
ad +=1; if (ad == 1)
{css = "1.css";} if (ad == 2)
{css = "2.css";} if (ad == 3)
{css = "3.css";} if (ad == 4)
{css = "4.css";} self.chun.href = Folder + css
//-->
</script>
方法二：
<script language="JavaScript">
var cssurlarr = ["1.css", "2.css", "3.css", "4.css"];
var cssurl = cssurlarr[Math.floor(Math.random()*cssurlarr.length)];
document.write(’<link href="’+cssurl+’" rel="stylesheet" type="text/css">’);
</script>
