<?php
error_reporting(0);
session_start();

if (empty($_SESSION['username']) AND empty($_SESSION['password'])){
    echo 'INI HALAMAN DEPAN, ANDA BELUM <a href="?modul=login">Login</a>';
}else{
    echo 'ANDA SUDAH LOGIN DENGAN username: <b>'.$_SESSION['username'].'</b> password: <b>'.$_SESSION['password'].'</b> <a href="?modul=logout">Logout</a>';
}

switch ($_GET['modul']){
    case "login":
         echo '
         <form name="login" action="ceksession.php" method="POST">
         Username :
         <input type="text" name="username">
         Password :
         <input type="text" name="password" >
         <button type="submit">Login</button>
         </form>';
    break;

    case 'logout':
        session_destroy();
        echo "<center>Anda telah sukses keluar sistem </center>";
        echo "<meta http-equiv='refresh' content='1;url=session.php'>";
    break;

    default:
        echo 'HALAMAN DEPAN <a href="?modul=login">Login</a>';
    break;
}

?>