> Didn't it start with asm.js It started even much earlier. At first Emscripten compiled to a plain Javascript subset, after this demonstrated 'usefulness' thi

> Didn't it start with asm.js It started even much earlier. At first Emscripten compiled to a plain Javascript subset, after this demonstrated 'usefulness' this JS subset was properly specificed into 'asm.js' which browsers could specifically target and optimize for. The next evolutionary step was WASM (which didn't immediately bring any peformance improvements over asm.js, but allowed further improvements without having to 'compromise' Javascript with features that are only useful for a compilation target).