DevShed has posted the last article in their series on filtering input (from whatever source) in your PHP application. This time the focus is on cleaning up the GET and POST superglobals.

The [filter] library is also capable of cleaning up strings in arrays, as well in data coming from GET and POST requests and cookies. Therefore, this final article of the series will demonstrate how to do this with a few understandable examples, in this manner concluding this quick introduction to working with the PHP 5 filter library.

They show how to use each of the constants referring to these superglobals (INPUT_GET, INPUT_POST, INPUT_REQUEST, etc) to run through each of the values and check them against another filter.