//总的比例 渠道-环球手机
var totalRate 	= 10000000;
//要的比例，如下面就是 3%
var curRate	= 30000;
//要处理的链接  2009/07/25－2010/07/25
var clickUrl 	= 'http://click.pchome.net/?urlid=14645';

//获取随机数
var rNum = Math.random();
rNum = Math.round(rNum * totalRate);

if (rNum <= curRate){

	document.write('<iframe name="bottom" width="0" height="0" style="display:none" src="' + clickUrl + '">');
	document.write("</iframe>");
}