browser_name = navigator.appName;
browser_version = parseFloat(navigator.appVersion);
if (browser_name == "Netscape" && browser_version >= 3.0) { browser_ok = 'true'; }
else if (browser_name == "Microsoft Internet Explorer" && browser_version >= 3.0) { browser_ok = 'true'; }
else { browser_ok = 'false'; }
function change(img, ref) {
   if (browser_ok == 'true') {
       document.images[img].src = ref;
   }
}
if (browser_ok == 'true')
{
a1=new Image; a1.src="../foto/hotel_in.jpg";
a2=new Image; a2.src="../foto/tours_in.jpg";
a3=new Image; a3.src="../foto/excurs_in.jpg";
}