It was a pleasent surprise to know we can build web app natively in non JavaScript language and there is W3C standard available to run those natively in Browser.

WebAssembly (abbreviated Wasm) is a binary instruction format for a stack-based virtual machine. Wasm is designed as a portable compilation target for programming languages, enabling deployment on the web for client and server applications.

WebAssembly Official Website

An interesting quick video to provide high level overview of WebAssembly in 2 minutes.