var baseurl = "images/"
var preloadFlag = false;

//preload
function doPreload() {
    if (document.images) {
		b_about_over = new Image(); b_about_over.src = baseurl + "b_about_over.gif";
		b_administration_over = new Image(); b_administration_over.src = baseurl + "b_administration_over.gif";
		b_courses_over = new Image(); b_courses_over.src = baseurl + "b_courses_over.gif";
		b_calendar_over = new Image(); b_calendar_over.src = baseurl + "b_calendar_over.gif";
		b_special_over = new Image(); b_special_over.src = baseurl + "b_special_over.gif";
		b_student_over = new Image(); b_student_over.src = baseurl + "b_student_over.gif";
		b_contact_over = new Image(); b_contact_over.src = baseurl + "b_contact_over.gif";

		return (preloadFlag = true);
    }
}

if (document.images) {
		b_about_off = new Image(); b_about_off.src = baseurl + "b_about_off.gif";
		b_administration_off = new Image(); b_administration_off.src = baseurl + "b_administration_off.gif";
		b_courses_off = new Image(); b_courses_off.src = baseurl + "b_courses_off.gif";
		b_calendar_off = new Image(); b_calendar_off.src = baseurl + "b_calendar_off.gif";
		b_special_off = new Image(); b_special_off.src = baseurl + "b_special_off.gif";
		b_student_off = new Image(); b_student_off.src = baseurl + "b_student_off.gif";
		b_contact_off = new Image(); b_contact_off.src = baseurl + "b_contact_off.gif";
}

//rollover code
function rollIn(imgName) {
    if (document.images && (preloadFlag == true)) {
        document[imgName].src = eval(imgName + "_over.src");
    }
}

function rollOut(imgName) {
    if (document.images){
        document[imgName].src = eval(imgName + "_off.src");
    }
}