or
<?php
print "<pre>";
print_r($_SERVER);
print "</pre>";
?>
otherwise, dive into your php config and have a play with:
always_populate_raw_post_data
Always populate the $HTTP_RAW_POST_DATA containing the raw POST data. Otherwise, the variable is populated only with unrecognized MIME type of the data. However, the preferred method for accessing the raw POST data is php://input. $HTTP_RAW_POST_DATA is not available with enctype="multipart/form-data".