Multiple values for a field

I’m interested in allowing users enter as many values as they want for a specific fields. Initially there will be only 1 field, and an “Add” button that created another copy of the field. Is this something currently available in the regular or pro version of the plugin? is this something that you are working on?

If not, I would like to implement it myself. Can you give me some pointers how should I start? I would be glad to contribute my implementation to the free version of the plugin when I’m done.

http://ww.wp.xz.cn/plugins/visual-form-builder/