Drupal Example of Ajax on Field group multiple using hook_form_alter

<?phpfunction mymodule_form_alter(&$form, $form_state, $form_id) {if($form_id == 'group_node_form'){ $ar__field_item = $form['fgm_node_YOURNODE_form_group_YOURGROUPNAME']['fields']['items'];// here content type is sales and group name is sl_multiple_product_group  foreach ($ar__product_item as $key => $value) {  $form['fgm_node_sales_form_group_sl_multiple_product_group']['fields']['items'][$key]['field_sl_quantity']['und']['value']['#ajax'] = array(                                                                                                              'callback' => 'get_unit_price',                                                                                                              'wrapper' => 'unit_price_callback_replace_' . $key,                                                                                                      );            $form['fgm_node_sales_form_group_sl_multiple_product_group']['fields']['items'][$key]['field_sl_product_price']['und']['value']['#ajax'] = array(                                                                                                              'callback' => 'get_unit_price',                                                                                                              'wrapper' => 'unit_price_callback_replace_' . $key,);$form['fgm_node_sales_form_group_sl_multiple_product_group']['fields']['items'][$key]['field_sl_unit_price']['und']['#suffix'] = '<div id="unit_price_callback_replace_' . $key . '">unit price will be here</div>'; }}}/** * ajax call back */function get_unit_price($form, $form_state) { $ar__product_item = $form_state['values']['fgm_node_sales_form_group_sl_multiple_product_group']['fields']['items'];    $arr__ajax_replace = array();    foreach ($ar__product_item as $key => $value) {                $sn__quantity = $form_state['values']['fgm_node_sales_form_group_sl_multiple_product_group']['fields']['items'][$key]['field_sl_quantity']['und']['value'];        $sn__price = $form_state['values']['fgm_node_sales_form_group_sl_multiple_product_group']['fields']['items'][$key]['field_sl_product_price']['und']['value'];        $sn__unit_price = $sn__quantity * $sn__price ;       $arr__ajax_replace[$key] = ajax_command_replace('#unit_price_callback_replace_' . $key, '<div id="unit_price_callback_replace_' . $key . '"><em>' . $sn__unit_price . '</em></div>');    }    return array(    '#type' => 'ajax',    '#commands' =>    $arr__ajax_replace  );}?>