function okno(windowURL,sirina,visina)
{
  visina += 50;
  var leftpos = (screen.width - sirina-10)/2;
  var toppos  = (screen.height - visina-60)/2;
  var nWindow = window;
  sirina+=20;
  
  nWindow = window.open(windowURL,'','width='+sirina+',height='+visina+',toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=yes,copyhistory=no,top='+toppos+',left='+leftpos);
}