login แล้วไม่ไปยังเพจที่ต้องการครับไม่ทราบว่าต้องแก้ยังไงบ้างครับ ขอบคุณครับ

 <?php
                                if (isset($_POST['login'])) {

                                    function clean($str) {
                                        $str = @trim($str);
                                        if (get_magic_quotes_gpc()) {
                                            $str = stripslashes($str);
                                        }
                                        return mysql_real_escape_string($str);
                                    }

                                    $username = clean($_POST['username']);
                                    $password = clean($_POST['password']);

                                    $query = mysql_query("select * from user where username='$username' and password='$password'") or die(mysql_error());
                                    $count = mysql_num_rows($query);
                                    $row = mysql_fetch_array($query);


                                    if ($count > 0) {
                                        $_SESSION['id'] = $row['user_id'];
                                        header('location:index.php');
										session_write_close();
                                        exit();
                                    } else {
                                        session_write_close();
                                        ?>

                                     
                                        <div class="alert alert-danger"><i class="icon-remove-sign"></i>&nbsp;Please Try Again</div>
                                        
                                        <?php