Untitled

<?php
        function authenticate()
                {

                $username = $_POST['username'];
                $pwd = $_POST['pwd'];

                $con = mysqli_connect("localhost","root","","bankapp");
                $rs = $con->query("select count(username) from logindetails where username='$username' and password='$pwd'");
                $row = $rs->fetch_row();
                $n = $row[0];

                $rs->free();
                $con->close();

                if($n <> 0)
                {
                        session_start();
                        $_SESSION['uname'] = $username;
                        header("Location: bal.php");
                }
                else
                {
                        echo "<b>Authentication Failed</b>";
                }

                }
?>
 <head>
                <title>DBS-Login</title>
        </head>
        <body>
                <h1>LOGIN</h1>
                <form method="POST">
                        <table border="1">
                                <tr>
                                        <td>Username </td>
                                        <td>
                                                <input type="text" name="username" />
                                        </td>
                                </tr>
                                <tr>
                                        <td>Password </td>
                                        <td>
                                                <input type="password" name="pwd" />
                                        </td>
                                </tr>
                                <tr align="center">
                                        <td colspan="2">
                                                <input type="submit" name="submit" value="Login" />
                                        </td>
                                </tr>
                        </table>
                </form>
                <?php
                        if(isset($_POST['submit'])){

     authenticate();
                        }
                ?>
        </body>
</html>