Simple credentials checking:
<? if (!isset($_SERVER['PHP_AUTH_USER'])) { header("WWW-Authenticate: Basic realm=\"Private Area\""); header("HTTP/1.0 401 Unauthorized"); print "Sorry - you need valid credentials to be granted access!\n"; exit; } else { if (($_SERVER['PHP_AUTH_USER'] == 'A') && ($_SERVER['PHP_AUTH_PW'] == 'B')) { print "Welcome to the private area!"; } else { header("WWW-Authenticate: Basic realm=\"Private Area\""); header("HTTP/1.0 401 Unauthorized"); print "Sorry - you need valid credentials to be granted access!\n"; exit; } } ?>