In a quick post to his blog Luc de Brouwer reminds us that we don't ever need to use $_GET or $_POST directly again thanks to PHP's filter extension.

This doesn't just work for $_GET and $_POST but also for $_SERVER and $_COOKIE variables. Check out the documentation for filter_input() on the PHP website.

He shows how it compares to the filtering that CodeIgniter has to offer with a few code examples - one showing a filtered fetch and the other showing how to grab the raw value from the superglobal (if you really need it, that is).