Untitled

<?php
session_start();
if($_SERVER['QUERY_STRING'] == "logout") {
    unset($_SESSION['authuser']);
    header("Location: " . $_SERVER['PHP_SELF']);
    exit;
}
$username = $_POST['username'];
$password = $_POST['password'];
$login    = $_POST['login'];
if($_SESSION['authuser'] != $adminuser) {
    if(!$login) {
        loginpage(false);
    }
    elseif(($username != $adminuser) || ($password != $adminpass)) {
        loginpage(true);
    }
    else {
        $_SESSION['authuser'] = $adminuser;
        header("Location: " . $_SERVER['REQUEST_URI']);
    }
}
header( 'index.php' ) ;
session_write_close();
?>
$adminuser = "test";
$adminpass = "test";


function loginpage($error) {
    echo "<html>\n<head>\n<title>Admin panel - Please login</title>\n";
    echo "</head>\n<body>\n";
    echo "<table style='width:100%;height:100%;'>\n<tr>\n<td align='center'>\n";
    echo "<form action='" . $_SERVER['REQUEST_URI'] . "' method='post'>\n";
    echo "<table border='1' width='300' cellspacing='0' cellpadding='4'><tr>\n";
    $formtitle = "Admin panel - Please login";
    if($error) $formtitle = "Wrong credentials!";
    echo "<th colspan='2'>" . $formtitle . "</th>\n";
    echo "</tr><tr>\n";
    echo "<td><p><b><label for='username'>Username:</label></b></p></td>\n";
    echo "<td><input type='text' name='username' id='username' size='30'></td>\n";
    echo "</tr><tr>\n";
    echo "<td><p><b><label for='password'>Password:</label></b></p></td>\n";
    echo "<td><input type='password' name='password' id='password' size='30'></td>\n";
    echo "</tr><tr>\n";
    echo "<td><b>Login:</b></td>\n";
    echo "<td><input type='submit' value=' Login &raquo; ' name='login'></td></tr></table></form>\n";
    echo "</td>\n</tr>\n</table>\n</body>\n</html>";
    exit;
}