$form = '<table><tr><td>' . $this->fetchMath( $sum ) . '</td>';
$form .= '<td>' . Xml::input( 'wpCaptchaWord', false, false, array( 'tabindex' => '1' ) ) . '</td></tr></table>';
- $form .= Xml::hidden( 'wpCaptchaId', $index );
+ $form .= Html::hidden( 'wpCaptchaId', $index );
return $form;
}