function clearPrefill(theInput, theDefaultValue) {
  if(theInput.value == theDefaultValue) {
    theInput.value = "";
  }
}

function addPrefill(theInput, theDefaultValue) {
  if(theInput.value == "") {
    theInput.value = theDefaultValue;
  }
}

function cbToggleAll(theCheckbox) {
  theStatus = theCheckbox.checked;
  document.getElementById('theater').checked    = theStatus;
  document.getElementById('nachtleben').checked = theStatus;
  document.getElementById('musik').checked      = theStatus;
  document.getElementById('kleinkunst').checked = theStatus;
  document.getElementById('klassik').checked    = theStatus;
  document.getElementById('kinder').checked     = theStatus;
  document.getElementById('ansonsten').checked  = theStatus;
}

function cbAllSelected() {
  if(document.getElementById('theater').checked    &&  
     document.getElementById('nachtleben').checked &&
     document.getElementById('musik').checked      &&
     document.getElementById('kleinkunst').checked &&
     document.getElementById('klassik').checked    &&
     document.getElementById('kinder').checked     &&
     document.getElementById('ansonsten').checked) {
     
    document.getElementById('alle').checked  = true;
  }
  else {
    document.getElementById('alle').checked  = false;
  }
}