function otevriPrezentaci(URL,jmeno) {
  window.open(URL,""+jmeno+"","width=800,height=610,left=30,top=30,toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=yes,resizable=0,copyhistory=0");
}

// otevirani do novych oken
function bar(url) {
  wasOpen = false;
  win = window.open(url);    
  return (typeof(win)=='object')?true:false;
}