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) {
		about_over = newImage("/images/nav_About-over.gif");
		research_over = newImage("/images/nav_Research-over.gif");
		corporate_over = newImage("/images/nav_Corporate-over.gif");
		institution_over = newImage("/images/nav_Institution-over.gif");
		contact_over = newImage("/images/nav_Contact-over.gif");
		parent_over = newImage("/images/nav_Parent-over.gif");
		preloadFlag = true;
	}
}