Hi @soojooko
Thanks for the reply.
1. Yes, all fields hidden by conditional logic will now save their value. This is why you may want to add in some custom logic to review the field’s key or name and bail early (as in my comment within the code)
2. You can add JS to the admin page like so:
http://www.advancedcustomfields.com/resources/adding-custom-javascript-fields/
3. Don’t worry about server, this won’t affect your code
Thanks
E