HTMLX+UI: Developing Native UI Webapp with Special Markups

I would like to suggest a new way to build an app with native UI, but made by with modern web technologies. This can be done by making up HTML and XML together, with extra markup to make it appear with native UI (Different appearance in different OSes). For example, we will use <header> instead of <div data-role=“header”>. This also involves a new version of rendering and layout engine, which allows special markups to be rendered with native UIs. This won’t lead to the extinction of recent mobile templates as JQM and Ionic framework, since they can support native UI rendering in case that the rendering engine failed to render in native UI; or even can extend capabilities of interactions. I called it HTMLX+UI because it involves HTML+XML+Native UI. The native UI rendering can also be made using CSS and JS.

This already exists as react-native.

I saw it, but the problem is my suggested markup will be useful for web apps that will activate by add to home screen instead of a webpage packed as a native app. Meanwhile the development of React Native is currently for iOS and Android, when there are other OSes such as Tizen, Windows and Firefox OS (Or maybe I suggest Facebook for development of other OSes and for online web pages.)

Sounds a bit like Mozilla’s XUL. Is it similar to what you’re proposing?