Untitled

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>
        <?php
        if (!empty($_POST)) {

            $servername = "localhost";
            $username1 = "dxa6145";
            $password1 = "hawaiisomeone";
            $dbname = "dxa6145";

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

            echo $username;
            echo $password;
            echo "000";
            $conn = new mysqli($servername, $username1, $password1, $dbname);

            if ($conn->connect_error) {
                die("Connection failed: " . $conn->connect_error);
            }

            echo $username;
            echo $password;
            echo "111";

            if ($_SERVER["REQUEST_METHOD"] == "POST") {
                if (isset($_POST['username']) && isset($_POST['password'])) {

                    $sql = "SELECT username FROM users WHERE username=" . $username . " AND password=MD5(" . $password . ")";
                    echo "232";
                    $result = $conn->query($sql);
                    echo "222";
                    if ($result->num_rows > 0) {
                            echo "333";
                        while ($row = $result->fetch_assoc()) {
                            echo "Welcome " . $row["username"];
                        }
                    } else {
                        echo "0 results";
                    }
                }
            }
        }
        ?>
        <form action="<?php echo $_SERVER["PHP_SELF"] ?>" method="post" name="form" novalidate>
            <fieldset>
                <legend>Login</legend>
                <br>Username: <input type="text" name="username">
                <br>Password: <input type="password" name="password">
                <input type="submit" value="Submit">
            </fieldset>
        </form>
    </body>
</html>