A dynamic, intelligent user interface for an on-line, virtual application whereby user input customizes the subsequent display of application data and queries presented to the user/applicant. The present invention includes a facility for intelligent editing, data state presentation, and error flagging and correction. In one embodiment of the present invention, the intelligent user interface is implemented as part of a series of dynamically generated web pages (a form set) presented to a user of an ecommerce Internet web site. This presentation is in the form of a collection of tabbed panes of data, the selected pane being displayed on a web page, wherein each pane contains one or more pages of data and queries. This organization and presentation of the virtual application provides re-entrant editing; error trapping, flagging, and correction; and easy navigation from sub-pane to sub-pane (page to page) within each pane and from pane to pane using the tabs and conventional browser Back and Forward button functionality.