var agent = navigator.userAgent.toLowerCase(); 
var mac = agent.indexOf('mac') != -1;
var w3c = document.getElementById ? true : false;
var iex = document.all ? true : false;
var ns4 = document.layers ? true : false;
var isOver = false;
var timer = null;

function subMenu(key, isOpen) {
	this.key = key;
	this.isOpen = isOpen;
	return this;
}

subMenus = new Array();
 
function getStyle(name, nest){
	nest = nest ? 'document.'+nest+'.' : '';
	return w3c ? document.getElementById(name).style : iex ? document.all[name].style : ns4 ? eval(nest+'document.'+name) : false;
}

function hideLayer(which) {
	timer = setTimeout('hideIt( \'' + which + '\' )',300);
}
function showLayer( which ) {
	clearTimeout(timer);
	for (i=1; i<=subMenus.length-1; i++) {
		if (subMenus[i].key!=which && subMenus[i].isOpen) {
			getStyle('subMenu'+subMenus[i].key).visibility = 'hidden';
		}
		if (subMenus[i].key=which ) subMenus[i].isOpen=true;
	}
	getStyle('subMenu' + which).visibility = 'visible';
}

function hideIt(which) {
	getStyle('subMenu' + which).visibility = 'hidden';
	for (i=1; i<=subMenus.length-1; i++) {
		if (subMenus[i].key!=which && subMenus[i].isOpen) {
			getStyle('subMenu'+subMenus[i].key).visibility = 'hidden';
		}
		if (subMenus[i].key=which ) subMenus[i].isOpen=false;
	}
}