Masuk-2

 <?php
session_start();
if(!empty($_SESSION['user'])){
header('Location: forum.php');
}
?>
        <div class="myform">
                <div class="container">
                <div class="halaman">

                    <div class="col-md-12" >
                    <h2>MASUK</h2>
                    </div>
                </div>
                </div>
                <div class="container">
                        <form action="" method="post">
                <div class="col-md-12">
                    <input type="text" placeholder="Username" name="email">
                </div>
                <div class="col-md-12">
                    <input type="password" placeholder="Password" name="password">
                </div>
                <div class="col-md-12">
                    <input type="submit" value="MASUK" name="login">
                </div>
            </form>
                        <?php

                        if(!empty($_POST['login'])){

                        $email = $_POST['email'];
                        $password = $_POST['password'];

                        $sql = mysql_query("SELECT m.email, m.password FROM tb_user m WHERE m.email= '$email' AND m.password=md5('$password')") or die(mysql_error());
                        $data = mysql_fetch_array($sql);
                        $cek = mysql_num_rows($sql);

                        if ($cek >= 1) {
                                        $_SESSION['user'] = $data['id_user'];
                                        echo "<script>alert('Anda Login dengan akun ".$email."');</script>";
                                        echo "<script>window.location.href = 'index.php?p=forum';</script>";

                        } else {
                                        echo "Email Atau Password Anda Salah!";
                                        echo " Tidak Punya Akun? <a href='?p=gabung'><h2>Register</h2></a>";
                        }
                        }
                        ?>
                </div>
        </div>

    </main>
    <!-- main page ends -->