home_on = new Image(30, 31);
   home_on.src = "/images/home_s.gif";
   home_off = new Image(30, 31);
   home_off.src = "/images/home.gif";

   register_on = new Image(30, 31);
   register_on.src = "/images/register_s.gif";
   register_off = new Image(30, 31);
   register_off.src = "/images/register.gif";
   
   nota_on = new Image(30, 31);
   nota_on.src = "/images/nota_s.gif";
   nota_off = new Image(30, 31);
   nota_off.src = "/images/nota.gif";
   
   download_on = new Image(30, 31);
   download_on.src = "/images/download_s.gif";
   download_off = new Image(30, 31);
   download_off.src = "/images/download.gif";
   
   support_on = new Image(30, 31);
   support_on.src = "/images/support_s.gif";
   support_off = new Image(30, 31);
   support_off.src = "/images/support.gif";
   
   contact_on = new Image(30, 31);
   contact_on.src = "/images/contact_s.gif";
   contact_off = new Image(30, 31);
   contact_off.src = "/images/contact.gif";

function img_act(imgName) {
      imgOn = eval(imgName + "_on.src");
      document [imgName].src = imgOn;
}

function img_inact(imgName) {
      imgOff = eval(imgName + "_off.src");
      document [imgName].src = imgOff;
}