After "magic" PoC demo by Steve Sanderson @ NDC
to run trans-complied C# in web browser (via WebAsssembly),
Microsoft is now committed to "real" product development of this interesting tool.
Web Apps can’t really do *that*, can they? - Steve Sanderson - YouTube
Blazor: a technical introduction by Steven Sanderson
aspnet/Blazor: Blazor is an experimental .NET web framework using C#/Razor and HTML that runs in the browser with WebAssembly @ GitHub
Some other languages could also run with WebAssembly in modern web browsers.
appcypher/awesome-wasm-langs: 😎 A curated list of languages that compile directly to or have their VMs in WebAssembly