WebAssembly

What is WebAssembly

Old rules, let's see the definition of WebAssembly:

WebAssembly is a binary instruction format for a stack-based virtual machine.

So, WASM is not a specific programming language, but a bytecode standard. Whatever we write any language, it will be finally compiled to LLVM bytecode implemented by the language's compiler itself.

Also, it doesn't mean their performance is the same.

There is a browser support list.

A WASM Demo

There is a demo base on Rust, to calculate fibonacci(30). I run it in different browsers, their logs are as below:

Chrome:

832040
9
832040
28

Safari:

832040
6
832040
35

Firefox:

TypeError: Response has unsupported MIME type

As we can see, in Chrome and Safari, wasm function is able to obviously improve CPU-bound tasks.