if (document) 
{image1on = new Image(); image1on.src = "images/nav_welcomeON.gif";
image1off = new Image(); image1off.src = "images/nav_welcome.gif";
image2on = new Image(); image2on.src = "images/nav_aboutON.gif";
image2off = new Image(); image2off.src = "images/nav_about.gif";
image3on = new Image(); image3on.src = "images/nav_contactON.gif";
image3off = new Image(); image3off.src = "images/nav_contact.gif"}

function turnOn(imageName) 
{if (document) {document[imageName].src = eval(imageName + "on.src");}}
function turnOff(imageName) 
{if (document) {document[imageName].src = eval(imageName + "off.src");}}