switch(ad_id){
	case 0701://下载首页
	var ad_id=5001
		document.write("<script language=\"JavaScript\" src=\"http://www.yesky.com/lbad/500.js\"></script>");break;
	case 0702://下载首页
	var ad_id=5002
		document.write("<script language=\"JavaScript\" src=\"http://www.yesky.com/lbad/500.js\"></script>");break;
	case 0703://下载首页
	var ad_id=5003
		document.write("<script language=\"JavaScript\" src=\"http://www.yesky.com/lbad/500.js\"></script>");break;
	case 0704://最终下载页
	var ad_id=5000001
		document.write("<script language=\"JavaScript\" src=\"http://www.yesky.com/lbad/500000.js\"></script>");break;
}