ป้องกันการ back กลับ หลังจาก logout ออกไปแล้ว ^^

<?
	session_start();
	if($_SESSION['UserID'] == "")
	{
		echo "Please Login!";
		exit();
	}

	if($_SESSION['Status'] != "ADMIN")
	{
		echo "This page for Admin only!";
		exit();
	}	
	
	mysql_connect("localhost","root","root");
	mysql_select_db("mydatabase");
	$strSQL = "SELECT * FROM member WHERE UserID = '".$_SESSION['UserID']."' ";
	$objQuery = mysql_query($strSQL);
	$objResult = mysql_fetch_array($objQuery);
?>

session_start();
if(!isset($_SESSION['LOGIN'])) {
	header('Location: login.php');
	die();
}

unset($_SESSION['LOGIN']);
session_destroy();
// หรือ
unset($_SESSION);
session_destroy();

<?php
    echo $this->session->userdata('logged_in');
?>

        $this->session->unset_userdata('logged_in');
        $this->session->sess_destroy();