I really like the feature set and feel of Dart. My only concern is lack of browser support.
As of May 2013, Microsoft Internet Explorer, Mozilla Firefox, Opera Software's Opera browser, and Apple Safari have no plan to embed a separate Dart VM [1].
What would it take to get these vendors to add support?
Because Dart compiles to JavaScript (which can even perform better than handwritten JavaScript to perform the same actions[1]), it runs everywhere. You don't need the Dart VM built into a browser for your Dart application to work; it already works today.
What would it take to get these vendors to add support?
I think that likely they would want to see more applications written in Dart. If a big company (like Facebook, for example) wrote a large application in Dart, other browser vendors would see both that big name developers are using Dart for their applications and they'd see the performance boost that browsers with the Dart VM built in take advantage of[2]. This would make it more compelling for them to include a Dart VM in their browser.
That shouldn't stop anyone. Dart works fine in every modern browser (and IE9), because you can compile it to JavaScript.
Generating minified Dart code is one line and compiling to minified JS is also just one line. If you do one in your build script, you can also do the other. It's a no-brainer, really.
As of May 2013, Microsoft Internet Explorer, Mozilla Firefox, Opera Software's Opera browser, and Apple Safari have no plan to embed a separate Dart VM [1].
What would it take to get these vendors to add support?
1: http://en.wikipedia.org/wiki/Dart_%28programming_language%29...