add custom JS script to pass parameters to form

Second question, I would like to write a js script for passing parameters form my web page(pin code) to the jet form (pin code), specially in your example RSVP Code.  to trigger the form associated with the pin number. will you form will accept passing parameters?

I'm not sure what RSVP code you are referring to, but you if wish to customize the form using custom scripts on your webpage, I suggest embedding it using the form's source code. Here's a guide on How-to-get-the-Full-Source-Code-of-your-Form.

Or if you mean you would like to pre-populate your form using URL parameters, here's a guide you can use: Prepopulating-Fields-to-Your-JotForm-via-URL-Parameters