Re: I thought that HTML5
Anyone serious about porting a large game as a webapplication uses WebGL.
For example, you take your existing OpenGL C++ game engine and 'just' recompile it with Emscripten/LLVM to 'asm.js' and run that in the browser:
(Mozilla and the game engine developers did that port in only 4 days !)
They ported MESS which emulates a large number of devices:
Or a DOS-emulator, so you can play 2400 old DOS games, like:
If DOS works, you can make WIndows 3.1 work too, so they did, with Internet access: