The GUI system for the NeXT was based on the Display PostScript system which in turn was based for the PostScript system designed for rendering to printers. Quartz in MacOS X is a further evolution of that.
replyInside HTML 5 you can find facilities for rendering documents and you can find facilities for rendering applications, including those forms. There is not a clear line between one and the other.
PostScript was for rendering graphics to a printer with a good emphasis on texts. Most of HTML is about marking up and styling interactive documents. There’s no clear line between the two, but an API for applications UI has different goals than one for document typesetting (even interactive one).
replyHTML have a lot of tools for devex, but if you’re going for a good codebase and simple implementation for a desktop application, QT is way easier.