if (document.images) {
	button1up = new Image();
	button1up.src = 'images/top_nav_home.gif';
	button1over = new Image();
	button1over.src = 'images/top_nav_home_over.gif';
	button2up = new Image();
	button2up.src = 'images/top_nav_courses.gif';
	button2over = new Image();
	button2over.src = 'images/top_nav_courses_over.gif';
	button3up = new Image();
	button3up.src = 'images/top_nav_why.gif';
	button3over = new Image();
	button3over.src = 'images/top_nav_why_over.gif';
	button4up = new Image();
	button4up.src = 'images/top_nav_about.gif';
	button4over = new Image();
	button4over.src = 'images/top_nav_about_over.gif';
	button5up = new Image();
	button5up.src = 'images/top_nav_request.gif';
	button5over = new Image();
	button5over.src = 'images/top_nav_request_over.gif';
	button6up = new Image();
	button6up.src = 'images/top_nav_search.gif';
	button6over = new Image();
	button6over.src = 'images/top_nav_search_over.gif';
	button7up = new Image();
	button7up.src = 'images/top_nav_enrolbasket.png';
	button7over = new Image();
	button7over.src = 'images/top_nav_enrolbasket_over.gif';
}

function mouseup(imagename) {
	if (document.images) {
		document[imagename].src = eval(imagename+'up.src');
	}
}

function mouseover(imagename) {
	if (document.images) {
		document[imagename].src = eval(imagename+'over.src');
	}
}