if (mtDropDown.isSupported()) 
		{
			var ms = new mtDropDownSet(mtDropDown.direction.down, 0, 0, mtDropDown.reference.bottomLeft);

var	menu4	=	ms.addMenu(document.getElementById("mainmenu4"));
menu4.addItem("沧州周边",	"/index.php/news/guangda/1/cn/552/551.html","");
menu4.addItem("省内线路",	"/index.php/news/guangda/1/cn/553/551.html","");
menu4.addItem("国内线路",	"/index.php/news/guangda/1/cn/554/551.html","");

			mtDropDown.renderAll();
		}
		//初始菜单
		window.onload = init;