In this chapter, you learned about how JavaScript came to be and where it is today. You were also introduced to Object-oriented programming concepts and saw how JavaScript is not a classic OO language, but a prototypal one. Finally, you learned how to set up and use your training environment—the Firebug console. Now you're ready to dive into JavaScript and learn how to use its powerful OO features. For additional information on the topics discussed in this chapter, take a look at the following web pages.
On the YUI Theater (http://developer.yahoo.com/yui/theater/), there are several talks by Douglas Crockford that are highly recommended. Part 1 of the "Theory of the DOM" talks about browser history, and Part 1 of "The JavaScript Programming Language" talks about history of JavaScript (amongst other things).
For OOP concepts see the Wikipedia article (http://en.wikipedia.org/wiki/Object-oriented_programming) and Sun's Java documentation (http://java.sun.com/docs/books/tutorial/java/concepts/index.html), although the latter talks about OOP using classes.
For examples of what's possible today with JavaScript, take a look at the Yahoo! Widgets page (http://widgets.yahoo.com/), Google Maps (http://maps.google.com), or the JavaScript version of the Processing visualization language (http://ejohn.org/blog/processingjs/).