function preloadImages() {
if (document.images)
	{
	var btn_prefield_roll = new Image
		btn_prefield_roll.src = "images/btn_prefield_over.gif"
	var btn_fieldwork_roll = new Image
		btn_fieldwork_roll.src = "images/btn_fieldwork_over.gif"
	var btn_lab_roll = new Image
		btn_lab_roll.src = "images/btn_lab_over.gif"
	var btn_interpretation_roll = new Image
		btn_interpretation_roll.src = "images/btn_interpretation_over.gif"
	var btn_synthesis_roll = new Image
		btn_synthesis_roll.src = "images/btn_synthesis_over.gif"
	var btn_faqs_roll = new Image
		btn_faqs_roll.src = "images/btn_faqs_over.gif"
	var btn_native_tech_roll = new Image
		btn_native_tech_roll.src = "images/btn_native_tech_over.gif"
	var btn_glossary_roll = new Image
		btn_glossary_roll.src = "images/btn_glossary_over.gif"
	var btn_home_roll = new Image
		btn_home_roll.src = "images/btn_home_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()
	{
	window.history.go(-1);
	}