var navBtnsOn = new Array();

window.onload = function(){
	var folder = "/facilities/nav/";
	var navBtnStrs = new Array('office', 'facilities', 'arts', 'f1', 'f2', 'f3', 'f4', 'f5', 'f6', 'f7', 'f8', 'f9', 'f10', 'f11', 'f12', 'f13', 'f14', 'f15');
	var navBtns = new Array();
	for(var i in navBtnStrs){
		var navBtn = new NavElement(navBtnStrs[i], folder);
		navBtns[navBtnStrs[i]] = navBtn;
	}
	for(var i in navBtnsOn){
		navBtns[navBtnsOn[i]].setOn();
	}
}

function navImage(id, folder){
	var baseFolder = folder;
	this.imgOn = new Image();
	this.imgOn.src = baseFolder + id + "_on.gif";
	this.imgOff = new Image();
	this.imgOff.src = baseFolder + id + ".gif";
}

function NavElement(id, folder){
	this.id = id;
	if(document.getElementById && document.getElementById(id)){
		var domEl = document.getElementById(id);
		domEl.NavElement = this;
		if (document.images) {
			this.imgObj = new navImage(id, folder);
			domEl.onmouseover = NavElement.eMouseOver;
			domEl.onmouseout = NavElement.eMouseOut;
		}
	}
}
NavElement.eMouseOver = function(e){
	document.getElementById(this.id).src = this.NavElement.imgObj.imgOn.src;
}
NavElement.eMouseOut = function(e){
	document.getElementById(this.id).src = this.NavElement.imgObj.imgOff.src;
}
NavElement.prototype.setOn = function(){
	if(document.getElementById && document.getElementById(this.id)){
		var domEl = document.getElementById(this.id);
		domEl.src = this.imgObj.imgOn.src;
		domEl.onmouseover = null;
		domEl.onmouseout = null;
	}
}