if (document.images) {
aboutOn = new Image();
aboutOn.src = "images/about_mouse.gif";
aboutOff = new Image();
aboutOff.src = "images/about_choice.gif";

engineeringOn = new Image();
engineeringOn.src = "images/engineering_mouse.gif";
engineeringOff = new Image();
engineeringOff.src = "images/engineering_choice.gif";

expansionOn = new Image();
expansionOn.src = "images/expansion_mouse.gif";
expansionOff = new Image();
expansionOff.src = "images/expansion_choice.gif";

pressureOn = new Image();
pressureOn.src = "images/pressure_mouse.gif";
pressureOff = new Image();
pressureOff.src = "images/pressure_choice.gif";

contactOn = new Image();
contactOn.src = "images/contact_mouse.gif";
contactOff = new Image();
contactOff.src = "images/contact_choice.gif";

ovalOn = new Image();
ovalOn.src = "images/oval1.gif";
ovalOff = new Image();
ovalOff.src = "images/oval.gif";

oval2On = new Image();
oval2On.src = "images/oval2.gif";
oval2Off = new Image();
oval2Off.src = "images/oval.gif";

oval3On = new Image();
oval3On.src = "images/oval3.gif";
oval3Off = new Image();
oval3Off.src = "images/oval.gif";

oval4On = new Image();
oval4On.src = "images/oval4.gif";
oval4Off = new Image();
oval4Off.src = "images/oval.gif";

oval5On = new Image();
oval5On.src = "images/oval5.gif";
oval5Off = new Image();
oval5Off.src = "images/oval.gif";
}

function activate(image_name) {
if (document.images) {
document[image_name].src = eval(image_name + "On.src");
}
}
function deactivate(image_name) {
if (document.images) {
document[image_name].src = eval(image_name + "Off.src");
}
}

function oval2on(image_name) {
if (document.images) {
document[image_name].src = eval(image_name + "2On.src");
}
}
function oval2off(image_name) {
if (document.images) {
document[image_name].src = eval(image_name + "2Off.src");
}
}

function oval3on(image_name) {
if (document.images) {
document[image_name].src = eval(image_name + "3On.src");
}
}
function oval3off(image_name) {
if (document.images) {
document[image_name].src = eval(image_name + "3Off.src");
}
}

function oval4on(image_name) {
if (document.images) {
document[image_name].src = eval(image_name + "4On.src");
}
}
function oval4off(image_name) {
if (document.images) {
document[image_name].src = eval(image_name + "4Off.src");
}
}

function oval5on(image_name) {
if (document.images) {
document[image_name].src = eval(image_name + "5On.src");
}
}
function oval5off(image_name) {
if (document.images) {
document[image_name].src = eval(image_name + "5Off.src");
}
}