if (document.images)
{
homeon = new Image();	
homeon.src = "nav/home_on.jpg";
portfolioon = new Image();	
portfolioon.src = "nav/portfolio_on.jpg";
contacton = new Image();	
contacton.src = "nav/contact_on.jpg";
linxon = new Image();	
linxon.src = "nav/links_on.jpg";

//-----

homeoff = new Image();	
homeoff.src = "nav/home_off.jpg";
portfoliooff = new Image();	
portfoliooff.src = "nav/portfolio_off.jpg";
contactoff = new Image();	
contactoff.src = "nav/contact_off.jpg";
linxoff = new Image();	
linxoff.src = "nav/links_off.jpg";

}
function imgOn(imgName)
{
if (document.images)
{
document[imgName].src = eval(imgName + "on.src");
}
}
function imgOff(imgName)
{
if (document.images)
{
document[imgName].src = eval(imgName + "off.src");
}
}