Just a note for people developing with xhtml... this applies to the source examples too as they all have xhtml-strict doctypes. When these are rendered correctly as xhtml (i.e. mime served up as application/xhtml+xml) then the correct behaviour is to disallow document.write in javascript (http://www.w3.org/MarkUp/2004/xhtml-faq#docwrite).
This breaks all the example pages which use MochiKit.js (5kb) to do dynamic importing of all the other modules. The workaround is simple: with xhtml, use the packed version of mockikit. However this means there is no convenient dev version of the source files for xhtml... Also, I'm inclined to think that document.write in this context, though a nifty trick, might be better left out.
