login.php

<!DOCTYPE html>
<?php
    include "koneksii.php";

if($_POST['username']) {
    $user = $_POST['username'];
    $pass = $_POST['password'];

    $sql = "SELECT * FROM user WHERE username = '$user' and password ='$pass'";
    $q = mysql_query($sql);
    $row = mysql_fetch_array($q);
    $name = $row['username'];
    if (!empty($row['username']))
    {
        echo '<script> alert("Welcome!!"); </script>';
        echo '<script type="text/javascript">
                window.location="index.php"
            </script>';
    }
    else
    {
        echo '<script> alert("GAGAL!!"); </script>';
    }

}

?>
    <html>
        <head>
        <meta charset="UTF-8">
        <title>Login</title>
        <link href="http://danny4rt.blogspot.co.id/favicon.ico" rel="icon" type="image/x-icon"/>
        <link rel="stylesheet" type="text/css" href="style.css">
        <!--[if lt IE 9]>
        <script>
            document.createElement("article");
            document.createElement("aside");
            document.createElement("footer");
            document.createElement("header");
            document.createElement("main");
            document.createElement("nav");
            document.createElement("section");
        </script>
        <![endif]-->
        </head>
        <body background="img/bg1.jpg">
}
}
<center>
    <style>
    section {
        text-align: center;
        height: 200px;
        width: 600px;
        background-color: #0ee060;
        margin-top: 5px;
        padding: 7px;
        padding-bottom: 5px;
        padding-top: 5px;
        border-radius: 20px;
        position: relative;

    }

    article {
        height: 200px;
        background-color: #c8fff7;
        margin-top: 5px;
        padding: 12px 22px;
        border-radius: 20px;
        position: relative;
    }
    </style>


    <section>
                <h2>Login</h2>
                <article>
                    <header>
                <form name="form1" id="form1" action="login.php">
                    Username:
                        <input type="text" name="username" size="30">
                <br><br>
                   Password:
                        <input type="password" name="passsword" size="30">
                <br><br>

                        <input type="submit" name="submit"value="login">
                </form>
                    </header>
                </article>
     </section>
    </center>
</html>