if (document.images)
   {
     homeon= new Image();
     homeon.src="images/home_hi.gif";
     abouton= new Image();
     abouton.src="images/about_hi.gif";
     contacton= new Image();
     contacton.src="images/contact_hi.gif";
     productson= new Image();
     productson.src="images/products_hi.gif";
     serviceson= new Image();
     serviceson.src="images/services_hi.gif";
     linkson= new Image();
     linkson.src="images/links_hi.gif";

     homeoff= new Image();
     homeoff.src="images/home.gif";
     aboutoff= new Image();
     aboutoff.src="images/about.gif";
     contactoff= new Image();
     contactoff.src="images/contact.gif";
     productsoff= new Image();
     productsoff.src="images/products.gif";
     servicesoff= new Image();
     servicesoff.src="images/services.gif";
     linksoff= new Image();
     linksoff.src="images/links.gif";
   }

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

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