The Rules of Unobtrusive JavaScript
http://www.456bereastreet.com/archive/200711/the_rules_of_unobtrusive_javascript/

Johansson, Roger
456 Berea Street
2007

Abstract:

One of the most important things to keep in mind when writing JavaScript for the Web is to make it unobtrusive, since You cannot rely on JavaScript being available.Sadly, there are many developers who do not seem to spend any energy at all on considering how to do that. Instead they choose to blindly forge ahead and assume that everybody who comes visiting will have full support for JavaScript and use a mouse.