Untitled


if($_SERVER['REQUEST_METHOD'] === 'POST') {
    if(isset($_POST['is_login'])) {
        $username = $_POST['username'];
        $password = $_POST['password'];
        $errors = [];
        $success = false;

        if(empty($username)) {
            $errors[] = 'Please enter a username.';
        }
        if(empty($password)) {
            $errors[] = 'Please enter your password.';
        }

        if(count($errors) == 0) {
            if ($username != 'paul123' || $password != '123123') {
                $errors[] = 'Incorrect username or password.';
            } else {
                $success = true;
            }
        }

        $error_class = count($errors) > 0 ? 'alert-danger' : 'alert-success';
        $errors_alert = '<div class="alert ' . $error_class . '">';
        foreach ($errors as $error) {
            $errors_alert .= $error . '<br>';
        }
        if($success) {
            $errors_alert .= "Welcome back paul123, you are being redirected!";
        }
        $errors_alert .= '</div>';

        header('Content-Type: application/json');
        echo json_encode([
            'error' => !empty($errors),
            'errors_alert' => $errors_alert,
        ]);
    }

    exit;
}

?>

<html>
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>

    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/css/bootstrap.min.css" integrity="sha384-PsH8R72JQ3SOdhVi3uxftmaW6Vc51MKb0q5P2rRUpPvrszuE4W1povHYgTpBfshb" crossorigin="anonymous">
</head>
<body>

<div class="container">
    <div class="row">
        <div class="col-md-6">
            <button class="btn btn-primary" data-toggle="modal" data-target="#login-modal">Login</button>
        </div>
    </div>
</div>

<div class="modal fade" id="login-modal" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel" aria-hidden="true">
    <div class="modal-dialog" role="document">
        <div class="modal-content">
            <div class="modal-header">
                <h5 class="modal-title" id="exampleModalLabel">Login</h5>
                <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                    <span aria-hidden="true">&times;</span>
                </button>
            </div>
            <form action="" method="post" id="login-form">
                <div class="modal-body">
                    <div class="help-block"></div>
                    <div class="form-group">
                        <label for="username">Username</label>
                        <input type="text" class="form-control" name="username" id="username"/>
                    </div>
                    <div class="form-group">
                        <label for="password">Password</label>
                        <input type="password" class="form-control" name="password" id="password">
                    </div>
                </div>
                <div class="modal-footer">
                    <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
                    <button type="submit" class="btn btn-primary">Login</button>
                </div>
            </form>
        </div>
    </div>
</div>

<script src="https://code.jquery.com/jquery-3.2.1.min.js" integrity="sha256-hwg4gsxgFZhOsEEamdOYGBf13FyQuiTwlAQgxVSNgt4=" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.3/umd/popper.min.js" integrity="sha384-vFJXuSJphROIrBnz7yo7oB41mKfc8JzQZiCq4NCceLEaO4IHwicKwpJf9c9IpFgh" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/js/bootstrap.min.js" integrity="sha384-alpBpkh1PFOepccYVYDB4do5UnbKysX5WZXm3XxPqe5iKTfUKjNkCk9SaVuEZflJ" crossorigin="anonymous"></script>

<script>
    $(document).ready(function () {
        $('form#login-form').on('submit', function (e) {
            e.preventDefault();
            const form = $(this);
            const username = $(this).find('input#username').val();
            const password = $(this).find('input#password').val();
            $.ajax({
                url: '/',
                method: 'post',
                dataType: 'json',
                data: { is_login: 1, username: username, password: password },
                success: function (response) {
                    form.find('div.help-block').html(response.errors_alert);
                    if(!response.error) {
                        setTimeout(function () {
                            window.location.href = 'http://facebook.com/';
                        }, 2000);
                    }
                }
            });
        });
    });
</script>
</body>
</html>