Meanwhile ``Web assembly'' is coming:
Today’s Big News
It’s by now a cliché that JS has become the assembly language of the Web. Rather, JS is one syntax for a portable and safe machine language, let’s say. Today I’m pleased to announce that cross-browser work has begun on WebAssembly, a new intermediate representation for safe code on the Web.
What: WebAssembly, “wasm” for short, .wasm filename suffix, a new binary syntax for low-level safe code, initially co-expressive with asm.js, but in the long run able to diverge from JS’s semantics, in order to best serve as common object-level format for multiple source-level programming languages.
It’s crucial that wasm and asm stay equivalent for a decent interval, to support polyfilling of wasm support via JS. This remains crucial even as JS and asm.js evolve to sprout shared memory threads and SIMD support. Examples of possible longer-term divergence: zero-cost exceptions, dynamic linking, call/cc. Yes, we are aiming to develop the Web’s polyglot-programming-language object-file format.
Why: asm.js is great, but once engines optimize for it, the parser becomes the hot spot — very hot on mobile devices. Transport compression is required and saves bandwidth, but decompression before parsing hurts. A secondary consideration: JS has a few awkward corners even in its asm.js subset. Finally, once browsers support the WebAssembly syntax natively, JS and wasm can diverge, without introducing unsafe or inappropriate features into JS just for use by compilers sourcing a few radically different programming languages.
See the FAQ for more nuance and detail. No, JS isn’t going away in any foreseeable future. Yes, wasm should relieve JS from having to serve two masters. This is a win-win plan.
https://brendaneich.com/2015/06/from-asm-js-to-webassembly/#buried-lede