if (document.images) {

   // Menu
   btn_home_on            = new Image();
   btn_home_on.src        = "images/rrol-voce-menu-home-on.png";
   btn_60esimo_on         = new Image();
   btn_60esimo_on.src     = "images/rrol-voce-menu-60esimo-on.png";
   btn_societa_on         = new Image();
   btn_societa_on.src     = "images/rrol-voce-menu-societa-on.png";
   btn_storia_on          = new Image();
   btn_storia_on.src      = "images/rrol-voce-menu-storia-on.png";
   btn_app_on             = new Image();
   btn_app_on.src         = "images/rrol-voce-menu-app-on.png";
   btn_camp_on            = new Image();
   btn_camp_on.src        = "images/rrol-voce-menu-camp-on.png";
   btn_minirugby_on       = new Image();
   btn_minirugby_on.src   = "images/rrol-voce-menu-minirugby-on.png";
   btn_seven_on           = new Image();
   btn_seven_on.src       = "images/rrol-voce-menu-seven-on.png";
   btn_old_on             = new Image();
   btn_old_on.src         = "images/rrol-voce-menu-old-on.png";
   btn_videos_on          = new Image();
   btn_videos_on.src      = "images/rrol-voce-menu-videos-on.png";
   btn_images_on          = new Image();
   btn_images_on.src      = "images/rrol-voce-menu-images-on.png";
   btn_contact_on         = new Image();
   btn_contact_on.src     = "images/rrol-voce-menu-contact-on.png";
   btn_sponsor_on         = new Image();
   btn_sponsor_on.src     = "images/rrol-voce-menu-sponsor-on.png";

   // Menu
   btn_home_off           = new Image();
   btn_home_off.src       = "images/rrol-voce-menu-home-off.png";
   btn_60esimo_off        = new Image();
   btn_60esimo_off.src    = "images/rrol-voce-menu-60esimo-off.png";
   btn_societa_off        = new Image();
   btn_societa_off.src    = "images/rrol-voce-menu-societa-off.png";
   btn_storia_off         = new Image();
   btn_storia_off.src     = "images/rrol-voce-menu-storia-off.png";
   btn_app_off            = new Image();
   btn_app_off.src        = "images/rrol-voce-menu-app-off.png";
   btn_camp_off           = new Image();
   btn_camp_off.src       = "images/rrol-voce-menu-camp-off.png";
   btn_minirugby_off      = new Image();
   btn_minirugby_off.src  = "images/rrol-voce-menu-minirugby-off.png";
   btn_seven_off          = new Image();
   btn_seven_off.src      = "images/rrol-voce-menu-seven-off.png";
   btn_old_off            = new Image();
   btn_old_off.src        = "images/rrol-voce-menu-old-off.png";
   btn_videos_off         = new Image();
   btn_videos_off.src     = "images/rrol-voce-menu-videos-off.png";
   btn_images_off         = new Image();
   btn_images_off.src     = "images/rrol-voce-menu-images-off.png";
   btn_contact_off        = new Image();
   btn_contact_off.src    = "images/rrol-voce-menu-contact-off.png";
   btn_sponsor_off        = new Image();
   btn_sponsor_off.src    = "images/rrol-voce-menu-sponsor-off.png";
}

function tnImgOn(imgName) {
   if (document.images) {
      document[imgName].src = eval(imgName + "_on.src");
   }
}

function tnImgOff(imgName) {
   if (document.images) {
      document[imgName].src = eval(imgName + "_off.src");
   }
}