protected function updateFormField($field)
 {
     parent::updateFormField($field);
     if ($this->LaterThanID) {
         $fieldid = "UserForm_Form_" . $this->LaterThan()->getFormField()->ID();
         $field->setAttribute('data-rule-datelaterthan', $fieldid);
     }
     if ($this->EarlierThanID) {
         $fieldid = "UserForm_Form_" . $this->EarlierThan()->getFormField()->ID();
         $field->setAttribute('data-rule-dateearlierthan', $fieldid);
     }
 }
 /**
  * Return the validation information related to this field. This is 
  * interrupted as a JSON object for validate plugin and used in the 
  * PHP. 
  *
  * @see http://docs.jquery.com/Plugins/Validation/Methods
  * @return Array
  */
 public function getValidation()
 {
     $options = parent::getValidation();
     if ($this->LaterThanID) {
         $fieldid = "Form_Form_" . $this->LaterThan()->getFormField()->ID();
         $options['DateLaterThan'] = $fieldid;
     }
     if ($this->EarlierThanID) {
         $fieldid = "Form_Form_" . $this->EarlierThan()->getFormField()->ID();
         $options['DateEarlierThan'] = $fieldid;
     }
     return $options;
 }