This does not exist for Javascript. You can jump through hoops to compile other code to Javascript and hope that it works and works acceptably, that's it.
Javascript isn't assembly, it's the only language and it's terrible.
It wouldn't surprise me if we eventually come full circle and discard the DOM entirely. Each web application is just a giant <canvas> with QT or something compiled to JS providing the UI elements.
The shocking thing is that we are almost at a point where a solution that sounds as stupid as that is actually less contrived and complex than the current mess.
At this stage, if asm.js is to succeed, they need to show how us mortals can use it. I.e. it needs to part of a complete toolchain, or an ide.
asm.js using qt (without hacks) would be amazing. How do I help (when I can hardly wrap my head around it)?
The awesomeness of assembly language is that it's perfectly exact, deterministic and thus very predictable and efficient. No unnecessary indirection unless you build it yourself. No implicit type casting(infact, no types at all). Nothing. Just plain instructions with very specific semantics to build from.
Now how does JS(or even asm.js) fare with it's tons of indirection and ambiguous implicit typecasts compared to an actual assembly language? From a technical standpoint for a compile target the comparison is embarrassingly unfair, but hey, this is something which is supposedly "OK" and acceptable, right?