Howdy! Welcome to our community of more than 130.000 members devoted to web hosting. This is a great place to get special offers from web hosts and post your own requests or ads. To start posting sign up here. Cheers!
But normally code like that is only used maliciously, if forms were meant to be linked they would share a common database or have builtin handlers for interacting
The only legitimate use for code along these lines is a post-echo, which is used by paypal to authenticate transactions. That works by making a http post back to the server containing the same data as was just sent to the client, if the server returns VALID it is a legitimate transaction.