if (document) 
{
image1on = new Image(); image1on.src = "images/overviewON.gif";
image1off = new Image(); image1off.src = "images/overview.gif";
image2on = new Image(); image2on.src = "images/registerON.gif";
image2off = new Image(); image2off.src = "images/register.gif";
image3on = new Image(); image3on.src = "images/supportON.gif";
image3off = new Image(); image3off.src = "images/support.gif";
image4on = new Image(); image4on.src = "images/loginON.gif";
image4off = new Image(); image4off.src = "images/login.gif";
image7on = new Image(); image7on.src = "images/homeON.gif";
image7off = new Image(); image7off.src = "images/home.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");}}