JS, for the most part, does run identically on different browsers. With very few cases of truly undefined behavior, any other difference is either DOM stuff, or

JS, for the most part, does run identically on different browsers. With very few cases of truly undefined behavior, any other difference is either DOM stuff, or a bug. I've ported lots of apps to JS, and generally they just work across browsers. Even the Unreal Engine 3 demo runs on Chrome, JS was not what was holding it back. > It's still an effort to reinvent the wheel. When a 1:1 ratio is reached, you (not you in particular) will still have ended up spending time implementing a feature that already exists on your OS The OS can run it, but native apps are not portable, as I said before. That is what makes it worth reinventing some parts of OSes in browsers.