Yes, asm.js, which by now has been abandoned and superseded by WebAssembly. And while Chrome never really supported asm.js, they added some optimizations that benefitted code written in that style.

I think that may also have been a problem with asm.js. While the code would work as is because it's just JS, you won't get any performance guarantees because the runtime could just do its own thing instead of doing ahead-of-time compilation to optimized code.