You can submit a form to your own server. The user is likely to be warned about this.
There are two parts
- a professional programmer writes a web script / web app (CGI, PHP, ASP, something like that). It is installed on a web server of yours. It has a URL and a way of delivering information back to PDF forms.
- a forms programmer adds stuff to a PDF form to connect to the web script's URL and get back the information needed.