if (document.images) {
        button1on = new Image();
        button1on.src = "images/vlajka_slovakia_on.jpg";
        button1off = new Image();
        button1off.src = "images/vlajka_slovakia_out.jpg";
        button2on = new Image();
        button2on.src = "images/vlajka_uk_on.jpg";
        button2off = new Image();
        button2off.src = "images/vlajka_uk_out.jpg";

  
        }
        function img_act(imgname)  {
     if (document.images)   {
          imgon = eval(imgname + "on.src");
          document [imgname].src = imgon;
     }
}
                function img_inact(imgname)   {
     if (document.images) {
          imgoff = eval(imgname + "off.src");
          document [imgname].src = imgoff;
     }
}