The form has a Submit button, a Search button (custom button), some fields for providing search filters and a sublist to display the results of the search. When a user hits the search button, it should populate the sublist. When they hit the submit button, it should generate a file based on the sublist's items. I've written it so that the Search button just flags a hidden checkbox, then submits the page. The 'POST' handler then checks to see if that flag is set in the request params. If it is, it runs the search and populates the sublist. If not, it generates the file.