Event after filling the form or filling the form in the server?

Hello experts,

I have the following problem, when the PDF is loaded only the structure appears and after a brief time the form is newly a filling, I need to execute a code after this, and could not have found the event that helps me; another solution that you might help me would be that the form fills in the server and not in the client, but not how to do it, I wait could help me with this topic.

Thank you.

Sorry for my english.