Show/Hide Content with CSS and JavaScript
Today’s tutorial will show you how to hide away extra bits of content using CSS and JavaScript, to be revealed at the click of a button. This is a great technique, because displaying the additional content doesn’t require a refresh or navigation to a new page and all your content is still visible to search engine bots that don’t pay any attention to CSS or JavaScript.
Glazebrook, Rob L. CSSnewbie (2008). Articles>Web Design>Interaction Design>CSS