Parallel JavaScript Code

Question

Is it possible to run JavaScript code in parallel in the browser? I'm willing to sacrifice some browser support (IE, Opera, anything else) to gain some edge here.

Answer 1

If you don't have to manipulate the dom, you could use webworkers ... there's a few other restrictions but check it out @ http://ejohn.org/blog/web-workers/

Answer 2

Parallel.js has a nice API for multithreaded processing in Javascript. It runs both in web browsers and in node.

Answer 3

Perhaps it would be better to recode your JavaScript in something that generally runs faster, rather than trying to speed up the Javascript by going parallel. (I expect you'll find the cost of forking parallel JavaScript activities is pretty high, too, and that may well wipe out any possible parallel gain; this is common problem with parallel programming).

Javascript is interpreted in most browsers IIRC, and it is dynamic on top of it which means it, well, runs slowly.

I'm under the impression you can write Java code and run it under browser plugins. Java is type safe and JIT compiles to machine code. I'd expect that any big computation done in Javascript would run a lot faster in Java. I'm not specifically suggesting Java; any compiled language for which you can get a plug in would do.

As an alternative, Google provides Closure, a JavaScript compiler. It is claimed to be a compiler, but looks like an optimizer to me and I don't know much it "optimizes". But, perhaps you can use that. I'd expect the Closure compiler to be built into Chrome (but I don't know for a fact) and maybe just running Chrome would get your JavaScript compiler "for free".

EDIT: After reading about what about Closure does, as compiler guy I'm not much impressed. It looks like much of the emphasis is on reducing code size which minimizes download time but not necessarily performance. The one good thing they do in function inlining. I doubt that will help as much as switching to a truly compiled langauge.

EDIT2: Apparantly the "Closure" compiler is different than the engine than runs JavaScript in Chrome. I'm told, but don't know this for a fact, that the Chrome engine has a real compiler.