proseslogin.php

<?php
include 'koneksi.php';
session_start();

$username = $_POST ['username'];
$password = md5 ($_POST ['password']);

$sql = mysqli_query($link, "SELECT * FROM user WHERE username = '$username' AND password = '$password'");
$chek = mysqli_num_rows($sql);
$data = mysqli_fetch_row($sql);

if( $chek > 0 ){
    $_SESSION['status_login'] = "sudah_login";
    $_SESSION['username'] = $data[1];

    ?>
    <script type="text/javascript">
        alert('Berhasil login sebagai <?php echo $_SESSION['username']; ?>!');
        window.location.assign('list.php');
    </script>
    <?php
} else {
    ?>
    <script type="text/javascript">
        alert('Gagal login, mungkin username atau password anda salah!');
        window.location.assign('login.php');
    </script>
    <?php
}

?>