//modified by zengs@vip.sina.co.
function clearsecondmenu(){
	//该函数清空所有二级菜单；
	var temp = document.getElementsByTagName("div");
	for(var i=0;i<temp.length;i++){
		if(temp.item(i).className == "menuHover")
			temp.item(i).className = "menuNormal";
	}
}
function initbutton(firstlevel,secondlevel){
	//该函数显示特点的二级菜单，具体实现在js/library.js中
	clearsecondmenu();
	var tdtemp = document.getElementById(firstlevel);
	var atemp = tdtemp.getElementsByTagName("a").item(0);
	atemp.className = "initial";
	
	if(secondlevel==null) //就为了“首页”
		return;
	
	var divtemp = tdtemp.getElementsByTagName("div").item(0);
	tdtemp.className = "menuHover";
	divtemp.className = "menuHover";
	
	var tdtemp2 = document.getElementById(secondlevel);
	var atemp2 = tdtemp2.getElementsByTagName("a").item(0);
	atemp2.className = "initial2";
}
function expand(s){
	clearsecondmenu();
	var temptd = s;
	var d = temptd.getElementsByTagName("div").item(0);
	temptd.className = "menuHover";
	d.className = "menuHover";
}