ranimg = new Array();
ranimg[0] = "http://www.youyou.co.jp/images/banner/kaiteki3.jpg";
ranimg[1] = "http://www.cosday.jp/add/acos468.gif";
ranimg[2] = "http://www.cosday.jp/images/bn/you.gif";

ranurl = new Array();
ranurl[0] = "http://www.youclub.jp/";
ranurl[1] = "http://www.animate-costume.jp/";
ranurl[2] = "http://www.youyou.co.jp/";
chip = Math.floor(ranurl.length * Math.random());
document.write('<a href="'+ ranurl[chip] +'" target="_blank"><img src="'+ ranimg[chip] +'" border="0"></a>');