php - Undefined index in $_POST[...]

When I run the following code, I get this error:

Notice: Undefined index: user in C:\wamp\www\moviel.php on line 3

And also this:

Notice: Undefined index: pass in C:\wamp\www\moviel.php on line 4

I can't find the mistake. Where is the problem?

session_start();
$_SESSION['username'] = $_POST['user'];   // <- LINE 3
$_SESSION['userpass'] = $_POST['pass'];   // <- LINE 4
$_SESSION['authuser'] = 0;
// Check username and password information
if(($_SESSION['username'] == 'Joe')and

    ($_SESSION ['userpass'] == '12345')){
    $_SESSION['authuser'] = 1;
}else{
    echo "Sorry, but youd don`t have the permission to view this page, you loser!";
    exit();
}
?>






?>
$myfavmovie = urlencode("Life of Brian");
echo ""; 
echo "Click here to see information about my favorite movie!"; 
echo "";
echo "
";

echo "";
echo "Click here to see my top 5 movies.";
echo "";
echo "echo  "";
echo "Click here to see my top 10 movies"
?>