Untitled

<?php
if (!isset($_SESSION)){
    session_start();
}

include_once "functions.php";
/*
call function to check if username and password is valid($_POST["username"], $_POST["password"])
if yes - $_SESSION = function to get user data and go to dashboard
if no - message for wrong password or username
*/
if (isset($_POST, $_POST["username"], $_POST["password"])) {
    if( isUserValid($_POST["username"], $_POST["password"])){
        $_SESSION = getUser($_POST["username"]);
        header("Location: dashboard.php");
    }
    else {
        echo "Wrong username or password";
    }
}
?>


<!doctype html>
<html lang="en">
<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>login</title>
    <link rel="stylesheet" href="login.css">
</head>
<body>
<header>Welcome to MySvalka</header>
<!--
form with :
field for username
field for password
login button

link to register page
-->
<main>
    <div id="form">
        <form method="post" action="login.php" ">

        <label for="username">Username: </label>
        <input type="text" name="username" required><br>

        <label for="password">Password:&nbsp;</label>
        <input type="text" name="password" required><br>

        <input type="submit" name="login" value="Log in" id="submit">
        </form>
    </div>
    <div id="link"><a href="register.php">Register now</a></div>
</main>

<footer>Enjoy</footer>
</body>
</html>