**function views_ajax_form_wrapper($form_id, &$form_state)**
  * $form = drupal_build_form($form_id, $form_state);
  * $output = drupal_render($form);

**function drupal_build_form($form_id, &$form_state)**
  * $form = drupal_retrieve_form($form_id, $form_state);
  * drupal_prepare_form($form_id, $form, $form_state);
  * drupal_process_form($form_id, $form, $form_state);
  * return $form;