<?php
session_start();

if (isset($_POST['submit'])) {
    $username = $_POST['username'];
    $password = $_POST['password'];

    $safe_username = safe_post_value($username);
    $safe_password = safe_post_value($password);
    $hashed_password = password_hash($safe_password, PASSWORD_DEFAULT);
    $verified_password = password_verify($password, $hashed_password);

    $query = "SELECT * FROM `members` WHERE '$safe_username' = `username`";

    $result = mysqli_query($connection, $query);
    if ($result = mysqli_query($connection, $query)) {
        if ($verified_password){
            while ($row = mysqli_fetch_assoc($result)) {
                printf("%s, %sn", $row['username'], $row['password']);
            }
        }
    } else {
        $message = "error";
        echo $message;
    }
    mysqli_free_result($result);
}
?>
<form action="login.php" method="POST">
    <input type="text" name="username" placeholder="gebruikersnaam">
    <input type="password" name="password" placeholder="wachtwoord">
    <input type="submit" name="submit" value="verstuur">
</form>