function preloadImages() {
if (document.images)
	{
	var frontier_roll = new Image
		frontier_roll.src = "images/btn_wildwest_over.jpg"
	var onward_roll = new Image
		onward_roll.src = "images/btn_onward_over.jpg"
	var territorial_roll = new Image
		territorial_roll.src = "images/btn_territorial_over.jpg"
	var interactive_roll = new Image
		interactive_roll.src = "images/btn_interactive_over.jpg"
	var collections_roll = new Image
		collections_roll.src = "images/btn_collections_over.jpg"
	var treaties_roll = new Image
		treaties_roll.src = "images/btn_related_over.jpg"
	var arrow_roll = new Image
		arrow_roll.src = "images/btn_arrow_over.jpg"
	var next_roll = new Image
		next_roll.src = "images/btn_next_over.gif"
	var previous_roll = new Image
		previous_roll.src = "images/btn_previous_over.gif"
	var back_roll = new Image
		back_roll.src = "images/btn_back_over.gif"
	}
}

function changeImages(sName,sImage)
	{
	if (document.images)
		{
		document.images[sName].src = sImage
		}
	}

function openWindow(theURL,winName,features)
	{
	window.open(theURL,winName,features).focus();
	}

function closeWindow()
	{
	window.close();
	}

if (document.layers)
	{
	origWidth = innerWidth;
	origHeight = innerHeight;
	}
function reloadPage()
	{
	if (innerWidth != origWidth || innerHeight != origHeight)
	location.reload();
	}
if (document.layers)
	onresize=reloadPage;
	
function goHistory()
	{
	history.back();
	}