> Sharing code between server and client (browser) is much easier, and there is no alternative to javascript in the browser.

That's a fallacy, the environments have nothing in common, the coding styles and interactions don't either, the only things you're going to be able to meaningfully share are trivial helper libraries à la underscore..

> and writing server code in the same language simplifies things.

Why? How? Where? I see that assertion often, but I have yet to see it backed by anything but "because I said so".