[SOLVED] - Strange problem with POST data

Let's form action=''

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Form action = full url or route_to('route_name')

With form action='' don't work.
I tried with method='get' and it works.... the url becomes with ?name=Mario&lastname=Rossi&submit=submit.

i tried also with action="<?php echo base_url('ControllerName/function'); ?>" but with metod='post' not working.....

Thanks, tahnks, for your time with me........