Drupal 6 Autocomplete example

autocomplete callback

/**
 * Autocomplete ajax helper to retrieve autocomplete options from textual mcard
 * discount search.
 *
 * @param $search
 *   User entered search string.
 *
 * @return
 *   JSON listing of autocomplete search options.
 */
function mcard_search_autocomplete($search = '') {

  $matches = array('discount 1', 'discount 2', 'discount 3');

  watchdog('mcard', 'autocomplete search query: !query !args', array('!query' => '<pre>' . print_r($search, TRUE) . '</pre>', '!args' => '<pre>' . print_r($_GET, TRUE) . '</pre>'), WATCHDOG_NOTICE);

  /*if ($search) {

    $result = db_query_range("SELECT name FROM {users} WHERE LOWER(name) LIKE LOWER('%s%%')", $search, 0, 10); // only 10 results will show

    while ($user = db_fetch_object($result)) {

      $matches[$user->name] = check_plain($user->name);

    }

  }*/

  drupal_json($matches); //Returns the data in JSON format

}

form definition

 $form['search'] = array(
    '#type' => 'textfield',
    '#description' => t('Search for discounts'),
    '#autocomplete_path' => 'treasury/mcard/discounts/autocomplete',
  );

hook menu

/**
 * Implementation of hook_menu().
 */
function mcard_menu() {

  $items['admin/settings/mcard'] = array(
    'title' => 'Mcard',
    'description' => 'Adjust Mcard discount settings',
    'page callback' => 'drupal_get_form',
    'page arguments' => array( 'mcard_discount_settings' ),
    'access arguments' => array('administer mcard discounts'),
  );
  $items['admin/settings/mcard/discounts'] = array(
    'title' => 'Mcard discount settings',
    'description' => 'Adjust Mcard discount settings',
    'page callback' => 'drupal_get_form',
    'page arguments' => array( 'mcard_discount_settings' ),
    'access arguments' => array('administer mcard discounts'),
    'weight' => -5,
  );
  $items['treasury/mcard/discounts'] = array(
    'title' => 'Discounts',
    'description' => 'Search for discounts for holders of an MCard',
    'page callback' => 'mcard_discounts_homepage',
    'access arguments' => array('view mcard discounts'),
    'type' => MENU_CALLBACK,
  );
  $items['treasury/mcard/discounts/ajax'] = array(
    'title' => 'Ajax endpoint for search results',
    'description' => 'Ajax requests get posted here and return search results',
    'page callback' => 'mcard_search_results',
    'access arguments' => array('view mcard discounts'),
    'type' => MENU_CALLBACK,
  );
  $items['treasury/mcard/discounts/autocomplete/%'] = array(
    'title' => 'Ajax autocomple endpoint for textual search',
    'description' => 'Ajax requests get posted here and return autocomplete options',
    'page callback' => 'mcard_search_autocomplete',
    'page arguments' => array(4),
    'access callback' => TRUE,
    'type' => MENU_CALLBACK,
  );

  return $items;

}