Untitled

<?php
// Start the session
session_start();
$error = "";
if ($_SERVER['REQUEST_METHOD'] === "POST") {
    $connection = mysqli_connect("localhost", "root", "", "authdb");

    $username = mysqli_real_escape_string($connection, $_POST['username']);
    $pass = mysqli_real_escape_string($connection, $_POST['password']);
    $email = mysqli_real_escape_string($connection, $_POST['email']);

    if ($connection) {

        $query = " SELECT * FROM users WHERE username = '$username' AND password = '$pass' AND email='$email'  ";
        $res = mysqli_query($connection, $query);
        $data = mysqli_fetch_assoc($res);
        var_dump($data);
        if ($data) {
            $error = 'Session variable set.';
            $_SESSION["username"] = $_POST['username'];
        } else {
            $error = 'username not found.';
        }
    } else {
        die("Connection Failed!");
    }
}
?>

<!DOCTYPE html>
<html lang="en">

    <head>
        <title>Login</title>
        <link rel="stylesheet" type="text/css" href="./css/style.css">
        <link href="https://fonts.googleapis.com/css?family=Raleway:300,400,500,700" rel="stylesheet">
    </head>

    <body>
        <div id = "login-page">
            <div id = "form-box">
                <form class = "login-form" method="POST" action="login.php">
                    <input type = "text" name="username" placeholder = "username" />
                    <input type = "password" name="password" placeholder = "password" />
                    <input type = "email" name="email" placeholder = "password" />
                    <button>LOGIN</button>
                    <?php
                    echo "<BR>";
                    echo $error;
                    echo $_SESSION["username"];
                    ?>
                    <p class = "message">Not registered? <a href = "#">Create an account</a></p>
                </form>

            </div>
        </div>
    </body>

</html>