hide/show fieldsets based on product type dropdown. Validate required fields that r within fieldsets that are currently visible. Show msg detailing which required fields are empty, prevent form submission until required fields are completed.
Using $(':focus') gives no results in Firefox (tested using 10.0.1), but seems to work in other browsers.
$(document.activeElement) throws in Firefox (tested using 10.0.1) with "Permission denied to access property 'nodeType'."