Get 404 error after clicked on cancel during edit a comment

Into function ajax_comments_edit($comment)
link is build like that

$form_build['actions']['cancel'] = array(
    '#markup' => '<a class=\'use-ajax\' href="/ajax_comments/edit/cancel/' . $node->nid . '/' . $comment->cid . '">' . t('Cancel') . '</a>',
    '#weight' => 21,
  );

better used l() to dont get error 404

$form_build['actions']['cancel'] = array(
    '#markup' => l(t('Cancel'), 'ajax_comments/edit/cancel/' . $node->nid . '/' . $comment->cid, array('attributes' => array('class' => array('use-ajax')))),
    '#weight' => 21,
  );