根据先前的选择填充下拉菜单

$region = mysql_real_escape_string($_POST['region']);$query = "SELECt s.school FROM regions rINNER JOIN schools s ON (s.region_id = r.id)WHERe r.region LIKE '$region' ";  <<-- LIKE is case insensitive, '=' is NOT $result = $db->query($query);if not($result) then { die("error"); }while($row=$result->fetch_array(MYSQLI_BOTH)){  echo '<option value="'.$row[0].'">'.$row[1].'</option>';}