<form method="post" action="login1.php">
Name: <input type="text" name="name" /><br />
Password: <input type="text" name="password" /><br />
<input type="submit" value="Login" />

<?php
    function is_logged() {
        if (isset($_SESSION['username'])) { echo '<p>You are logged in as ' . $_SESSION['username'] . '.</p>'; }
        else { echo '<p>You are not logged in.</p>'; }
    }
    is_logged();
    if (isset($_POST['password']) && isset($_POST['name'])) {
        mysql_connect('xxxxt', 'xxxx', 'xxxxx') or error_log("Could not connect to database.");
        mysql_select_db('loginsys') or error_log("Could not select database.");
        $username = mysql_real_escape_string($_POST['name']);
        $password = $_POST['password'];
        $result = mysql_query("SELECT * FROM users WHERE username = '" . $username . "' AND password = '" . $password . "'") or error_log("MySQL query error.");
        if (mysql_num_rows($result)) {
            if (isset($_SESSION['username'])) { echo '<p>You are already logged in.</p>'; }
            else {
                session_start();
                $_SESSION['username'] = htmlspecialchars($username);
                echo '<p>Successfully logged in!</p>';
            }
        }
        else {
            echo "<p>Incorrect password!</p>";
            header('Location: login1.php');
        }
    }
?>