Add easy-to-absorb, interactive user documentation to your JavaScript apps with Intro.js. Learn from a sample tour implementation how to demonstrate your application’s features the modern way from within the app’s UI.
Source: Add interactive documentation to your JavaScript apps with Intro.js :: IBM developerWorks
For complex interactive apps and sites showing visitors how to use the site is always tricky. Intro.js can help by allowing you to create interactive tours that demonstrate how the app works. The tours are always available through an icon in the navigation.