I currently have a main form that has some form input boxes and a listbox and a button on it. What I want the user to do is click on the button which would open a modal page, they select an item from that page, the modal form then closes and the selected item is added to the listbox. I would like them to be able to add as many items to the listbox as they require. I can't refresh the main page because other entries may have been made to other input boxes. I also wouldn't mind being able to pass the listbox contents to the modal form to not show items already selected.
As far as I can tell I would have to use inline forms or <div> tags. I'm not too sure.
Any ideas or better ways to perform the above action would be appreciated.
Sorry about the lack of points, I'm starting to run low.