Javascript is a flexible functional language similar to Common Lisp and Scheme, if not in syntax, at least in spirit. Bruce Tate wrote a good overview JavaScript's language features that is well worth reading.

I find HTML's DOM model to be unpleasant to work with, but Javascript the language is fun to use. I have been using the Dojo toolkit a lot lately and the authors of Dojo have done a fine job of building a platform that insulates programmers from the hassles of DOM and browser incompatibilities.

I am currently working on another AI book (using Ruby for the examples) but I would enjoy later writing a Javascript book from my own perspective (a developer who wants to use the same Javascript skill set when developing using Ruby on Rails, Java, Common Lisp, etc.).