The beauty of javascript is that it is supported in multiple environments (various browsers, rhino, v8, etc). But with that comes VM specific implementations, a

The beauty of javascript is that it is supported in multiple environments (various browsers, rhino, v8, etc). But with that comes VM specific implementations, and that's real life. To truly achieve what the author said, programmer has to dumb-down their javascript to the lowest common denominator. Or have one common library to make sure all javascript features are supported, even if some have to be written in javascript. Take array comprehension for example (https://developer.mozilla.org/en/New_in_JavaScript_1.7 https://developer.mozilla.org/en/New_in_JavaScript_1.7). Rhino, since it's a Mozilla thing, supports it. How about IE? I'm not sure if V8 even supports that. Separation between server side and client side is bound to happen. Especially since it's a lot easier to use bleeding edge features on server side.