The recently released Dart 1.1 comes with better performance for the dart2js compiler and improves support for the server-side development. The language itself is pretty much on hold.
Opera will release new versions of their browser for mobile and desktop based on WebKit. They are also going to integrate Chromium.
Node.js 0.8 is out. It is faster, more stable, has major improvements in the Cluster module, a new Domain module and a new build that depends on GYP.
Debuggers in mobile web browsers are anemic at best. InfoQ takes a look at existing workarounds and tools like Weinre and JSConsole, as well as the upcoming changes in mobile browsers that will bring full debugging support. Also: the two mobile browsers that already live in the future and ship remote debugging support.