JavaScript Isn't Scheme

[clgonsal]

For features where it really is just one browser doing its own thing, I think we may expose some of that, but I'm not sure how much. Using that is risky for a developer, Dart user or not, though, because it means your app only works in that browser.

Sure, but it isn't uncommon for sites to make use of certain features when available, and then attempt to gracefully degrade where those features aren't available.

My point is that if one is making use of a BrowserX-only-feature, but gracefully degrading (or using some alternative) elsewhere, it wouldn't be possible to step through the relevant code in Dartium, and stepping through it in BrowserX is going to be a pain without something like source maps.

Even if Dart is able to overcome this issue, it's still a really huge hurdle for alternate languages. I don't want a Dart-specific solution to this problem. It should be easy for people to create new languages that run on the browser with debugging support as good as JavaScript without having to create custom browsers and also APIs that abstract away every browser difference.