[sunnya]

I didn't know that was possible. Even if you can compile Roslyn to JS to run on the client, you still need to compile most parts of the BCL as well, or else you still need to make a server call.

[lukasm]

Sure. You may try compile IL to js http://jsil.org/

[mattmanser]

Marvel at convoluted error messages! (JSIL is still in development. You will hit bugs)