<?php require_once('Connections/BE2.php'); 
 
$county='台北市';
$district='中山區';
if(isset($_POST['county'])){$county=$_POST['county']; }
if(isset($_POST['district'])){$district=$_POST['district']; }

mysql_select_db($database_BE2, $BE2);
// address_id county district street
$query_Rct2 = "SELECT address_id,street FROM address where county='$county' AND district='$district' order by street";
$result = mysql_query($query_Rct2, $BE2) or die(mysql_error());
$response=''; 
   while($row = mysql_fetch_assoc($result)) {
      $response .= '<option value="' .$row['address_id'] . '">' . $row['street'] . '</option>'; //Concatenate your response
   }
echo $response;
mysql_free_result($result);
?>