I have a select field which has ID name as 'region_code' well as its value. And I want pass ID in ajax. As you can see below, the input field is not included in any form. It has a value and the ID

Is it possible to get value in ajax as shown below?

  echo '<select id="region_code" onchange="show_region_code();">';

  $result = mysql_query("SELECT region_code, region_name FROM list_region");
  while($rows = mysql_fetch_array($result)) {                      
             echo "<option value=\"$rows[0]\">".$rows["1"].'</option>';
  }
  echo '</select>';

My ajax function as below

function show_region_code() {

     var region_code = $("#region_code").val();

     $.ajax ({
            type: "POST",
            url: "show_region_code.php",
            data: { region_code1: region_code },
              success: function(data) {
                     $("#region_code").html(data);
            }
     });
 }