Php drupal中的自动完成函数

我有一个自动完成的函数，如下所示：

function find_noreff_auto($string=NULL){
$matches = array();
db_set_active('data');
$result = db_query("SELECT * FROM reffnum where LOWER(noreff) LIKE LOWER('%%$string%%') AND journaled='0' AND noreff NOT IN (SELECT noreff from tmpreffnum) ORDER BY noreff ASC");
while ($row=db_fetch_object($result) )
{
$matches[$row->noreff.'-'.number_format($row->nominal,2)] = t($row->noreff.': '.number_format($row->nominal, 2));
}

drupal_json($matches);
drupal_set_message($matches);

}

此功能： 1.如果我写一些字符，它会从reffnum搜索noreff值 2.如果我选择一个值，它会给出如下结果：NOREFF123-1.000,00

以下是表格：

  $form['input']['noreff10'] = array(
  '#type' => 'textfield',
  '#title' => t('No Reff10'),
  '#size' => 60,
  '#default_value' => $noreff10,
  '#description' => 'Nominal from '.$noreff10.' is '.$nominalnoreff10,

  '#autocomplete_path' =>'noreff/autocomplete',
  '#ahah' => array(
      'event'   => 'change',
      'path'    => ahah_helper_path(array('inputan')),
      'wrapper' => 'inputan-wrapper',
     'method' => 'replace',
         'progress' => 'throbber',
  ),
  '#prefix' => '<div class="s-form">', '#suffix' => '</div>',
  );

我要10美元。我该怎么办？ $nominalnoreff10=$noreff10['NORMAL']；没有给我价值