Responding to dvcolgan's clarifying comment:
coffee-script library and jsdom to do the HTML parsing.
Exactly how you want to implement this would depend on the web framework you're using. You probably don't want the CoffeeScript compiler to run on every request (it's pretty fast, but it's still going to reduce the number of requests/second your server can handle); instead, you'd want to compile your HTML once and then serve the compiled version from a cache. Again, I don't know of any existing tools that do this, but it shouldn't be too hard to write your own.