Java Script for adding data signature to a general button

On my form I have a button for user to email the form to the next user in the workflow.  On a click event, the mailDoc scripts will be executed.  However, I would like to have a data signature tie to this event. Hope this provide you a little more detail on what I try to accomplish.

Thanks in advance for helping.  

It's not clear to me what sort of functionality you're seeking. Can you describe in detail what you mean by "add data signature"?