/**
  * @param String $html
  * @return 
  */
 public function onAfterRender($html)
 {
     parent::onAfterRender($html);
     if ($this->getField()->getConfig('showcalendar')) {
         Requirements::css(MULTIDATEFIELD_DIR . "/css/multidatefield.css");
         Requirements::javascript(MULTIDATEFIELD_DIR . "/thirdparty/jquery-multidatepicker/jquery-ui.multidatespicker.js");
         Requirements::javascript(MULTIDATEFIELD_DIR . "/javascript/MultiDateField.js");
     }
     return $html;
 }