I. Apache

Many of the environment variables can be found here:
http://www.php.net/manual/language.variables.predefined.php

Quickly view all POST variables :

  <?php print_r($HTTP_POST_VARS); ?>

An easier way to debug user-submitted data is with the print_r and var_dump
functions (check their manual entries to ensure your version of PHP support
them).

To find all available HTTP variables use:

print_r($HTTP_*_VARS);

For variables submitted via post use only:

print_r($HTTP_POST_VARS);

And for GET:

print_r($HTTP_POST_VARS);

And fun with $GLOBALS:

print_r($GLOBALS);


Note that data is immediately printed to the browser unless buffering is
used.

If you are trying to find a Handler to use with apache's mod_mime functions
(e.g. SetHandler).  Use the MIME type associated with php.

e.g. SetHandler application/x-httpd-php