> My statement was correct. It's not JavaScript, which is why you use a keyword to switch to a different compiler mode.

I'm afraid your statement really wasn't correct. asm.js is both syntactically and semantically JavaScript. OdinMonkey is a pure optimization; any observable divergence in behavior (other than timing, which of course all engines are allowed to do) is a bug that will be fixed. The fact that SpiderMonkey uses a prolog directive (not a keyword), which is also of course valid ECMAScript, to trigger a different kind of optimization does not change the fact that it is a valid implementation of JavaScript.