ajax_city.php

<?php
include('db/db.php');

//Database connection selection
$db=new db();
$db->db_connect();
$db->db_select();


if($_POST['id'])
{
$id=$_POST['id'];
$sql=mysql_query("select m.* from theatres t left join movies m on m.id=t.movies_id Left join location l on l.id=t.location_id where l.id='$id'");

while($row=mysql_fetch_array($sql))
{
$id=$row['id'];
$data=$row['name'];

$a=$a.'<option style="color:red" value="'.$id.'" >'.$data.'</option><br/>';
}

echo $a;
}
?>