I have a friend who's currently doing a web frontend for an HPC application in C++ with Wt [1]. It's trying to be like Qt on the desktop; basically all events are sent from the frontend to the backend and handled there, in a normal C++ application. Then the widgets render their updated state and that gets sent back to the browser for integration into the client-side view. Then you're just building applications out of widgets like with a regular old desktop application, which my friend is really happy about since he has a bit of experience with Qt and the like, but absolutely zero experience with HTML/CSS/JS.

[1] http://www.webtoolkit.eu/