public function executePreview(sfWebRequest $request)
 {
   $this->forward404Unless($request->isXmlHttpRequest() && $request->isMethod('post'));
   $this->setLayout(false);
   
   $commentText = sfNestedCommentTools::clean($request->getPostParameter('commentText'));
   return $this->renderText($commentText);
 }
 public function updateContentColumn($value)
 {
   return sfNestedCommentTools::clean($value);
 }