Miscellany

if ($num_rows == 1) {
	if (!isset($_SESSION['started'])) {
		session_start();
		$_SESSION['started'] = "true";
	}
	$_SESSION['username'] = $username;
	print "Successfully logged in as $username!  Click <a href='javascript:history.back()'>here</a> to go back!";
} else {
	print "You have entered an invalid username or password.  Click <a href='javascript:history.back()'>here</a> to go back!";
}