function ToggleVisibility(element) {
  if (element != null) {
    if (element.style.display == 'none') {
      element.style.display = '';
    }
    else {
      element.style.display = 'none';
    }    
  }
}

function ToggleEnabled(element) {
  if (element != null) {
    element.disabled != element.disabled;
    //alert(element.disabled);
  }
}