HTTP_USER_AGENT?

[Anon]

I've just started using PHP and I was working on the demo site using PHP and IIS. I've gotten PHP to run (I can pull up phpinfo) but I get this error when I try to use HTTP_USER_AGENT:

Notice: Undefined variable: HTTP_USER_AGENT in D:\wwwroot\default.php on line 100

All I'm trying to do is this:

<?php echo $HTTP_USER_AGENT ?>

What could I be doing wrong?

[Anon]

Nevermind. I found out that I had to use $HTTP_SERVER_VARS["HTTP_USER_AGENT"] instead of referencing the item directly.