Webassembly: an alternative to JavaScript

Webassembly (wasm) is a new and fast binary format for webcontent. It is supported by all big browser vendors, such as Microsoft, Mozilla, Google and WebKit. Developers can write C- and C++ extensions for browsers, which will be transformed by a LLVM-backend to wasm.

Further information:
https://brendaneich.com/2015/06/from-asm-js-to-webassembly/
https://blog.mozilla.org/luke/2015/06/17/webassembly/
Documentations: https://github.com/WebAssembly