[php] logout and redirecting session in php

the below one is the link in my php site.. after clicking this button the user's session should be terminated and he should be redirected again to the home page.. i have written the coding for this concept as follows but it shows me only a blank page(it is not redirected to the home page).. please correct my codings

<a href="Logout.php">
click here to log out</a>

codings in the Logout.php a follows

<?
session_start();
session_unset();
session_destroy();
ob_start();
header("location:home.php");
ob_end_flush(); 
include 'home.php';
//include 'home.php';
exit();
?>

<?php

session_start();

session_unset();

session_destroy();

header("location:home.php");

exit();

?>

<?php //initialize the session if (!isset($_SESSION)) {   session_start(); } 
// ** Logout the current user. **
$logoutAction = $_SERVER['PHP_SELF']."?doLogout=true";
if ((isset($_SERVER['QUERY_STRING'])) && ($_SERVER['QUERY_STRING'] != "")){
    $logoutAction .= "&". htmlentities($_SERVER['QUERY_STRING']); 
}

if ((isset($_GET['doLogout'])) &&($_GET['doLogout']=="true")) {
    // to fully log out a visitor we need to clear the session variables
    $_SESSION['MM_Username'] = NULL;
    $_SESSION['MM_UserGroup'] = NULL;
    $_SESSION['PrevUrl'] = NULL;
    unset($_SESSION['MM_Username']);  
    unset($_SESSION['MM_UserGroup']);
    unset($_SESSION['PrevUrl']);
    $logoutGoTo = "index.php";

    if ($logoutGoTo) {
        header("Location: $logoutGoTo");
        exit;
    }
} ?>

The simplest way to log out and redirect back to the login or index:

<?php
    if (!isset($_SESSION)) { session_start(); }
    $_SESSION = array(); 
    session_destroy(); 
    header("Location: login.php"); // Or wherever you want to redirect
    exit();
?>

<?php
session_start();
session_destroy();
header("Location: home.php");
?>

Use this instead:

<?
session_start();
session_unset();
session_destroy();

header("location:home.php");
exit();
?>