<?php
if(isset($_POST['login'])){
    echo "bla";
    $username = $_POST["username"];
    $passwort = $_POST["password"];

    $abfrage = "SELECT username, password FROM Benutzer WHERE username LIKE '$username' LIMIT 1";
    $ergebnis = mysql_query($abfrage);
    $row = mysql_fetch_object($ergebnis);

if($row->userpassword == md5($passwort))
    {
    $_SESSION["username"] = $username;
    $_SESSION["angemeldet"] = true;
    echo "<script language=\"javascript\">alert('".$_SESSION['username'].", you are now logged in')</script>";
    echo "bla";
        }
else
    {
    echo "<script language=\"javascript\">alert('Wrong username or password.')</script>";
    }
    echo "bla";

}

?>