Does browser JavaScript allow for SIMD or Vectorized operations?
SIMD.js was part of JavaScript. There was also experimental implementations in Firefox and Chrome but now SIMD.js has been taken out of active development in TC39 and removed from Stage 3. It is not being pursued by web browsers for implementation anymore. SIMD operations exposed to the web are under active development within WebAssembly, with operations based on the SIMD.js operations.
WebAssembly SIMD Status
- Chrome : In Development
- Firefox : No public signals
- Edge : In Development
- Safari : No public signals
Status of SIMD in LLVM Wasm backend and web engines:
Proposal: Implementation Status
The state of SIMD in JavaScript is partly a practical and a developmental problem.
Practical
Web browsers are kind of like virtual machines. This means they need a ton of drivers for hardware. The drivers for exposing the few shaders and whatnot for WebGL are significantly different than the arbitrary kernel execution required for SIMD operations.
Developmental
Hypothetically, one could just wrap WebGL to make it a general purpose GPU computer and someone has attempted to with gpgpu.js. However, it's got finicky support and is probably slower than just directly piping a kernel to the GPU.
Conclusion
The web isn't ready for SIMD yet. There are quite a few big companies working to make it ready. Until then, you're going to have to rely on WebWorkers for large batches of numerical computations.