if (document.images) {
	imageNav1on = new Image();
	imageNav1on.src = "/portal/graphics/header/topnav_aboutlib_over.gif";
	imageNav1off = new Image();
	imageNav1off.src = "/portal/graphics/header/topnav_aboutlib.gif";

	imageNav2on = new Image();
	imageNav2on.src = "/portal/graphics/header/topnav_forms_over.gif";
	imageNav2off = new Image();
	imageNav2off.src = "/portal/graphics/header/topnav_forms.gif";

	imageNav3on = new Image();
	imageNav3on.src = "/portal/graphics/header/topnav_aboutsite_over.gif";
	imageNav3off = new Image();
	imageNav3off.src = "/portal/graphics/header/topnav_aboutsite.gif";
	
	imageNav4on = new Image();
	imageNav4on.src = "/portal/graphics/header/topnav_libhome_over.gif";
	imageNav4off = new Image();
	imageNav4off.src = "/portal/graphics/header/topnav_libhome.gif";

}

/* our new navControl Object */
nav = new Object();
/* how many elements in our nav */
/*
	this value will need to be modified
	if more elements are added to the nav
*/
nav.Items = 3;

/* the prefix of the navigation ID */
nav.SubItemPrefix = 'navSub';
nav.ImageIDPrefix = 'imageNav';

/* time for menu to stay after mouse out in MS */
nav.timeLimit = 500; 

/* current nav item */
nav.CurrentNavItem = '';
/* current image */
nav.CurrentImage = '';
nav.CurrentImageID = '';
nav.StaticImage = '';
nav.blankLeftImageID = '';


/* set up obj methods */
nav.hideAll = hideAll;
nav.changeImages = changeImages;
nav.showItem = showItem;
nav.action = action;
nav.setCurrent = setCurrent;
nav.subNavAction = subNavAction;
nav.startTimer = startTimer;
nav.stopTimer = stopTimer;

/* set current */
function setCurrent(navID, subNavID)
{
	nav.CurrentNavItem = document.getElementById(subNavID);
	nav.CurrentImage = document.getElementById(navID);
	nav.CurrentImageID = navID;
	return true;
}
 

function startTimer()
{
	nav.timer = setTimeout('nav.hideAll()', nav.timeLimit);
}

function stopTimer()
{
	clearTimeout(nav.timer);
}

/* show Item */
function showItem()
{
	if( nav.CurrentNavItem ){
		nav.CurrentNavItem.style.display = "block";
		nav.CurrentNavItem.style.visibility = "visible";
	}
	if(nav.CurrentImage){
		nav.changeImages(nav.CurrentImageID, nav.CurrentImageID+'on');
	}

	return true;
}

/* hide all the elements */
function hideAll()
{
	for( i=0; i < nav.Items; i++ )
	{
		/* since we start with navSub1 */
		id = i+1;
		eleId = nav.SubItemPrefix+id;
		imageId = nav.ImageIDPrefix+id;
		ele = document.getElementById(eleId);
		ele.style.display = "none";
		ele.style.visbility = "hidden";
		nav.changeImages(imageId, imageId+'off');
	}
	
	return true;
}

function action(navID, subNavID)
{
	if (document.getElementById){
		/* set current nav item */
		nav.stopTimer();
		nav.setCurrent(navID, subNavID);
		nav.hideAll();
		nav.showItem();
	}
}

function subNavAction()
{
	nav.stopTimer();
}

/*** Nav Controls ***/
function displayMenu(navID, subNavID)
{
	if (document.getElementById){
		nav.action(navID, subNavID);
	}
	return true;
}

function clearNav()
{
	if (document.getElementById){
		nav.startTimer();
	}
	return true;
}


function changeImages() {
	if (document.images) {
		for (var i=0; i<changeImages.arguments.length; i+=2) {
			document[changeImages.arguments[i]].src = eval(changeImages.arguments[i+1] + ".src");
		}
	}
}