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

var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		msc = newImage("images/msc_student_on.gif");
		bshs = newImage("images/bshs_student_on.gif");
		preloadFlag = true;
	}
}

function rollover (image_object, image_name)
{
  image_object.src = "images/" + image_name;
}