I need to delete a file after processing the form.

Because of security reasons, the assigned user can see the file while processing the form. After finishing it (click on Processed button), he can't see the file if he accesses the form through Inbox > Completed tasks.

I think a solution would be deleting the file after triggering the button "Processed" (or any another label). I dont' need this file anymore.

Does anyone can help me to build this javascript code?