1 ajax.inc ajax_prepare_response($page_callback_result)

Converts the return value of a page callback into an Ajax commands array.


$page_callback_result: The result of a page callback. Can be one of:

  • NULL: to indicate no content.
  • An integer menu status constant: to indicate an error condition.
  • A string of HTML content.
  • A renderable array of content.

Return value

An Ajax commands array that can be passed to ajax_render().:

Related topics


core/includes/ajax.inc, line 581
Functions for use with Backdrop's Ajax framework.


function ajax_prepare_response($page_callback_result) {
  $commands = array();
  if (!isset($page_callback_result)) {
    // Simply delivering an empty commands array is sufficient. This results
    // in the Ajax request being completed, but nothing being done to the page.
  elseif (is_int($page_callback_result)) {
    switch ($page_callback_result) {
      case MENU_NOT_FOUND:
        $commands[] = ajax_command_alert(t('The requested page could not be found.'));

        $commands[] = ajax_command_alert(t('You are not authorized to access this page.'));

        $commands[] = ajax_command_alert(filter_xss_admin(token_replace(config_get_translated('system.core', 'maintenance_mode_message'))));
  elseif (is_array($page_callback_result) && isset($page_callback_result['#type']) && ($page_callback_result['#type'] == 'ajax')) {
    // Complex Ajax callbacks can return a result that contains an error message
    // or a specific set of commands to send to the browser.
    $page_callback_result += element_info('ajax');
    $error = $page_callback_result['#error'];
    if (isset($error) && $error !== FALSE) {
      if ((empty($error) || $error === TRUE)) {
        $error = t('An error occurred while handling the request: The server received invalid input.');
      $commands[] = ajax_command_alert($error);
    else {
      $commands = $page_callback_result['#commands'];
  else {
    // Like normal page callbacks, simple Ajax callbacks can return HTML
    // content, as a string or render array. This HTML is inserted in some
    // relationship to #ajax['wrapper'], as determined by which jQuery DOM
    // manipulation method is used. The method used is specified by
    // #ajax['method']. The default method is 'replaceWith', which completely
    // replaces the old wrapper element and its content with the new HTML.
    $html = is_string($page_callback_result) ? $page_callback_result : backdrop_render($page_callback_result);
    $commands[] = ajax_command_insert(NULL, $html);
    // Add the status messages inside the new content's wrapper element, so that
    // on subsequent Ajax requests, it is treated as old content.
    $commands[] = ajax_command_prepend(NULL, theme('status_messages'));

  return $commands;