if (document.images) {
var about_off = new Image();
about_off.src = "images/about_off.gif";
var about_on = new Image();
about_on.src = "images/about_on.gif";
var cert_off = new Image();
cert_off.src = "images/cert_off.gif";
var cert_on = new Image();
cert_on.src = "images/cert_on.gif";
var contact_off = new Image();
contact_off.src = "images/contact_off.gif";
var contact_on = new Image();
contact_on.src = "images/contact_on.gif";
var exer_off = new Image();
exer_off.src = "images/exer_off.gif";
var exer_on = new Image();
exer_on.src = "images/exer_on.gif";
var loc_off = new Image();
loc_off.src = "images/loc_off.gif";
var loc_on = new Image();
loc_on.src = "images/loc_on.gif";
var phil_off = new Image();
phil_off.src = "images/phil_off.gif";
var phil_on = new Image();
phil_on.src = "images/phil_on.gif";
var testi_off = new Image();
testi_off.src = "images/testi_off.gif";
var testi_on = new Image();
testi_on.src = "images/testi_on.gif";
}

function act(imgName) {
if (document.images)
document[imgName].src = eval(imgName + '_on.src');
}
function inact(imgName) {
if (document.images)
document[imgName].src = eval(imgName + '_off.src');
}