Probably yes ;) Javascript is already compiled down to machine code for quite a while. And if the code is very 'static' (like asm.js) the JS engine will leave the code alone, and the garbage collector will be inactive. Performance between asm.js and WebAssembly is pretty much the identical at the moment, with 10% to 20% disadvantage vs native there isn't that much room for drastic improvement. I think WebAssembly will mostly bring improvements for 64-bit integer operations and vector math, but for average integer and floating point code, JS is already very fast.