// 下拉菜单
var dhmenu = new Array;
dhmenu[0] = "level_0_div";
dhmenu[1] = "level_1_div";
dhmenu[2] = "level_2_div";
dhmenu[3] = "level_3_div";
dhmenu[4] = "level_4_div";
dhmenu[5] = "level_5_div";
function showMenu(n){
	var obj = document.getElementById(dhmenu[n]); 
	if(obj.style.visibility=="visible") return;
	obj.style.visibility="visible";
	for (i=0;i<6;i++){
		mObj = document.getElementById(dhmenu[i]);
		if (i!=n) mObj.style.visibility="hidden";
}
}
function hideMenu(n){
	var obj = document.getElementById(dhmenu[n]);
	obj.style.visibility="hidden";
}