function popupCalendarInt(elem) {
  if (elem == null) {
    return false;
  }
  if ( typeof(popupWin) != "undefined" ) {
     popupWin.close();
  }
  popupWin = window.open('/js/calendar.jsp','Kalender','toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=yes,copyhistory=yes,width=231,height=250,modal=yes');

  popupWin.HuHu = elem.id;
  popupWin.AllowPast = false;
  return false;
}

function popupCalendarFerien(elem) {
  //alert("book");
  if (elem == null) {
    return false;
  }
  if ( typeof(popupWin) != "undefined" ) {
     popupWin.close();
  }
  popupWin = window.open('book_docs/js/calendarFerien.jsp','KalenderFerien','toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=yes,copyhistory=yes,width=231,height=250,modal=yes');

  popupWin.HuHu = elem.id;
  popupWin.AllowPast = false;
  return false;
}

//function calculateBack()
//{
//  var startdate = document.getElementById('termin').value;
//  var arrstartdate = startdate.split('.');
//  var test = arrstartdate[0]+document.getElementById('naechte').value;
//  var datestartdate = new Date(arrstartdate[2], arrstartdate[1]-1, test);
//  document.getElementById('rueckreisedatum').innerHTML = datestartdate;
//}