Drupal 7 - Form API - Populating field value by ajax request via ajax_command

d7_form_api_ajax_via_ajax_command.txt

<?php

/**
 * Implements hook_form_FORM_ID_alter().
 */
function hook_form_id_form_alter(&$form, &$form_state) {

  $form['field_text_1']['#prefix'] = "<div id='text-1-value'>";
  $form['field_text_1']['#sufix'] = "</div>";

  $form['submit'] = array(
    '#type' => 'button',
    '#value' => t('Search'),
    '#ajax' => array(
      'callback' => 'update_field',
      'wrapper' => 'text-1-value',
      'method' => 'replace',
      'effect' => 'fade',
    ),

  );
  return $form;
}

function update_field($form, &$form_state) {
  $form['field_text_1']['und'][0]['value']['#value'] = 'BAM';

  return array(
    '#type' => 'ajax',
    '#commands' => array(
      ajax_command_replace("#text-1-value", render($form['field_text_1'])),
    ),
  );
}