[tomjen3]

Oh definitely. Or rather we need a vm designed to write code that can be optimized to run fast (personal dream, allow me to optionally include typing information. I already type my JS, might as well make it run better).

This means that the vm would be lowlevel enough that performance would start to approach that of native code, with complete freedom for the programmer to write the code for it in any language he desired.

The browser would then be able to execute this code instead of the corresponding Javascript file (e.g you compiler outputs two different object codes, one minified javascript for legacy browsers, one modern vm file for modern browsers).

[TazeTSchnitzel]

You'll be disappointed to know that Dart doesn't use bytecode.

[kmontrose]

There's a wholly unconvincing argument as to why Dart isn't pushing a VM as well, http://www.dartlang.org/articles/why-not-bytecode/ . Might as well be titled "Why not the JVM?" in my opinion.

[TazeTSchnitzel]

It isn't unconvincing. They make the case that bytecode is not assembly in reality, and constrains what you can do in languages compiled to it.

[kmontrose]

Nonsense, a VM is what it's defined to be. If you wanted the x86 (or ARM, or PPC, etc.) instruction set to be your bytecode, you've got it.

That article starts from the assumption that any in browser VM will resemble the JVM; which is a faulty assumption. In fact, any in browser VM would have to be very different from the JVM since Rule 0 for any such VM would be "acceptable Javascript performance".

From that article:

> Meanwhile, JVMs don't do these optimizations. Since all types are statically

> known, the compiler knows exactly how much storage they need and what

> operations they support. It can then generate appropriate tight code for those

> types. This is fast if your language is statically typed, but if you're trying to

> compile a dynamically typed language to the JVM, it won't be able to run as fast as a

> VM that can assume dynamic typing all the way down and optimize specifically

> for that.

A whole wasted paragraph. Of course a browser VM wouldn't be statically typed, that'd make compiling/running Javascript a bear. One would hope there'd be some system of type-hinting, because eliminating dynamic dispatch is really low hanging fruit in terms of optimization, but JVM/CLR-style static typing? Madness.

[tomjen3]

Dart isn't relevant, since google isn't pushing it nearly hard enough.