//Preload supported images.

   if (document.images) {

      tab1on = new Image();
      tab1on.src = "images/homepage/tabactive_products.jpg";
      tab1off = new Image();
      tab1off.src = "images/homepage/tab_products.jpg";
      
      tab2on = new Image();
      tab2on.src = "images/homepage/tabactive_downloads.jpg";
      tab2off = new Image();
      tab2off.src = "images/homepage/tab_downloads.jpg";

      tab3on = new Image();
      tab3on.src = "images/homepage/tabactive_contact.jpg";
      tab3off = new Image();
      tab3off.src = "images/homepage/tab_contact.jpg";

      tab4on = new Image();
      tab4on.src = "images/homepage/tabactive_news.jpg";
      tab4off = new Image();
      tab4off.src = "images/homepage/tab_news.jpg";

      tab5on = new Image();
      tab5on.src = "images/homepage/tabactive_about.jpg";
      tab5off = new Image();
      tab5off.src = "images/homepage/tab_about.jpg";

      tab6on = new Image();
      tab6on.src = "images/homepage/tabactive_careers.jpg";
      tab6off = new Image();
      tab6off.src = "images/homepage/tab_careers.jpg";

      tab7on = new Image();
      tab7on.src = "images/homepage/tabactive_map.jpg";
      tab7off = new Image();
      tab7off.src = "images/homepage/tab_map.jpg";

      }

//function to change images to rollover state

function rollon(image_name) 
   {
   if (document.images)  
      {
      document[image_name].src = eval(image_name + 'on.src');
      }
   }

//change images back

function rolloff(image_name)
   {
   if (document.images)
      {
      document[image_name].src = eval(image_name + 'off.src');
      }
   }