function authenticate($username,$password) {
	global $users_table;
	$username = strtolower($username);
	$result = do_mysql_query("SELECT * FROM $users_table WHERE username='$username'");
    $row = mysql_fetch_array($result);
	if ($password==$row["password"]) {
	    return true;
	} else {
		return false;
	}
}