Accessible Context-Sensitive Help with Unobtrusive DOM Scripting
http://dev.opera.com/articles/view/accessible-context-sensitive-help-with-u/

Palinkas, Frank M.
Opera
2008

Abstract:

This article demonstrates two methods of calling context-sensitive help in a web form: the Field Help Method and Form Help Method, in which unobtrusive DOM/JavaScript is employed to achieve the desired result. It also serves to illustrate the separation of the Structure and Behavior layers of a web page. Graceful degradation is employed to make sure that the help information is accessible if JavaScript is disabled or not available in a user agent.