function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

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

var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		home_over = newImage("images/home-over.gif");
		articles_over = newImage("images/articles-over.gif");
		interactive_over = newImage("images/interactive-over.gif");
		events_over = newImage("images/events-over.gif");
		preloadFlag = true;
	}
}

function hideTab1(classpassed){
	document.getElementById('tab2a').className=classpassed;
	document.getElementById('tab2b').className=classpassed;
	document.getElementById('tab3a').className=classpassed;
	document.getElementById('tab3b').className=classpassed;
	document.getElementById('tab4a').className=classpassed;
	document.getElementById('tab4b').className=classpassed;
	showTab1('showTab')
}
function showTab1(classpassed){
	document.getElementById('tab1a').className=classpassed;
	document.getElementById('tab1b').className=classpassed;
}
function hideTab2(classpassed){
	document.getElementById('tab1a').className=classpassed;
	document.getElementById('tab1b').className=classpassed;
	document.getElementById('tab3a').className=classpassed;
	document.getElementById('tab3b').className=classpassed;
	document.getElementById('tab4a').className=classpassed;
	document.getElementById('tab4b').className=classpassed;
	showTab2('showTab')
}
function showTab2(classpassed){
	document.getElementById('tab2a').className=classpassed;
	document.getElementById('tab2b').className=classpassed;
}
function hideTab3(classpassed){
	document.getElementById('tab1a').className=classpassed;
	document.getElementById('tab1b').className=classpassed;
	document.getElementById('tab2a').className=classpassed;
	document.getElementById('tab2b').className=classpassed;
	document.getElementById('tab4a').className=classpassed;
	document.getElementById('tab4b').className=classpassed;
	showTab3('showTab')
}
function showTab3(classpassed){
	document.getElementById('tab3a').className=classpassed;
	document.getElementById('tab3b').className=classpassed;
}
function hideTab4(classpassed){
	document.getElementById('tab1a').className=classpassed;
	document.getElementById('tab1b').className=classpassed;
	document.getElementById('tab2a').className=classpassed;
	document.getElementById('tab2b').className=classpassed;
	document.getElementById('tab3a').className=classpassed;
	document.getElementById('tab3b').className=classpassed;
	showTab4('showTab')
}
function showTab4(classpassed){
	document.getElementById('tab4a').className=classpassed;
	document.getElementById('tab4b').className=classpassed;
}