What stops sites from shipping Dart only and not shipping the JavaScript?
What stops sites from shipping Dart only and not shipping the JavaScript?
That's right, and historically encouraging authors to use vendor-specific stuff by making that the easiest thing to do, whether it be filter:progid:DXImageTransform, WebKit prefixes, ActiveX banking plugins, or what have you, has been bad for user choice.
To give just one example, WebKit asked authors not to rely on WebKit prefixes, but they did and now we're in the situation where just yesterday I wasn't able to use clippercard.com on Firefox for Android because the design was so broken as to be unusable. :(
I agree that sites should do it, but developers have not done this in the past. If Chrome has a commanding market share, history says that developers will not bother to target other browsers.