Intelligent Navigation Bars with JavaScript and CSS
http://www.cssnewbie.com/intelligent-navigation/

Glazebrook, Rob L.
CSSnewbie
2008

Abstract:

I’ve developed a trick over the years that I’ve used on a number of websites now for making my sites’ navigation bars “intelligent” or “self-aware.” By that, I mean that the navigation bar automatically knows which tab/button/whatever should be considered the currently active link, without having to manually specify a class or ID on either the body tag or on the links themselves.