Hop.js: A multitier JavaScript
hop.inria.fr
hop.inria.fr
However at the time it was Scheme-based. You wrote Scheme in one codebase, which was then compiled appropriately to (client- and server-side) JS plus HTML. At some point in the past 5 years it must've been overhauled to use JS as the unifying language instead of Scheme? I can't find a history page on the site or any information about that change, but I'd be curious to read about it.
I stumbled upon the project while researching languages that allow me to write code for the server and the client with the same language, codebase and API. A few more interesting examples are Opa [0], Skew [1] and of course Dart [2].
0: http://opalang.org 1: http://skew-lang.org 2: https://www.dartlang.org