function rand_number(n)
{
	var x;
	x=Math.round(Math.random()*100);
	x%=n;
	return x;
}

var img = new Array();
var n=rand_number(3);
var url;

img[0]='<img src="http://www.99bb.com/banners/zh/468_60_d2_zh.jpg" width="468" height="60">';
img[1]='<img src="http://www.99bb.com/banners/zh/b05_468_60_zh.gif" width="468" height="60">';
img[2]='<img src="http://www.99bb.com/banners/zh/468_60_zh.gif" width="468" height="60">';

url = '<a TARGET="_new" href="http://banner.99bb.com/banner.html?id=200212120004-2">' + img[n] + '</a>';

document.write(url);