protected function renderValue()
 {
     $hp = Codendi_HTMLPurifier::instance();
     $html = '<input type="' . $this->getInputType() . '" 
                      id="' . $this->id . '" 
                      name="' . $hp->purify($this->name, CODENDI_PURIFIER_CONVERT_HTML) . '" 
                      value="' . parent::renderValue() . '" ';
     foreach ($this->params as $key => $value) {
         $html .= $key . '="' . $value . '" ';
     }
     $html .= ' />';
     return $html;
 }