How to add a button in a form apart from submit/reset buttons?

How to add a button in a form apart from submit/reset buttons?

I have a small task.

1) For a multi-line field in my form, I need a button adjacent to it. This button when clicked should run a script and capture the data as input into the field. How can this be done?

2) The script should run a stored executable jar file. Is it possible in zoho, kindly help.

Thanks.