AjaxLine

There is an interesting article about creating interfaces  with jQuery UI Draggablles and Droppables on Dev102 site. Here's short excerpt from it:

I’ve just taken a look at how a rich interface for creating invitations could be created with jQuery UI’s draggables and resizables.

The goal here is to allow two basic elements to be dragged and resized in a work area to which they are limited, texts and images. They are not to be allowed to be dragged or scaled outside of the work area.

Source: Dev102.