To help you out with your further exploration of JavaScript and MooTools, I've compiled a very short list of resources that you can check out. The selection isn't exhaustive in any sense, but simply reflects base points for further study and experimentation.
The recent resurgence of JavaScript has certainly raised the number of JavaScript related resources, both in print and online form. The following are the ones that stand out as being essential references that are consulted by most developers.
ECMAScript Language Specifications. The official language specifications are, of course, the first resources that any serious JavaScript developer should consult. Because they are formal documents, the language specifications can be hard to get through at times. However, it is important that you take time reading through the specifications, since all implementations are judged by their conformance to these documents. Since the third edition is still the most widely supported version of the language, I recommend that you read through third Edition specification first (
http://www.ecma-international.org/publications/standards/Ecma-262-arch.htm). Afterwards, you should read the fifth Edition specification (http://www.ecma-international.org/publications/standards/Ecma-262.htm) to familiarize yourself with the new features of ECMAScript 5.JavaScript the Definitive Guide by David Flanagan (Fifth Edition; 2006, O'Reilly). Often called the Rhino Book because of its cover, this book is one of the best JavaScript books in terms of scope and content. There have certainly been a lot of changes since this book was first published, but it still remains an essential reference for any serious JavaScript developer.
Mozilla Developer Network (
https://developer.mozilla.org/). The Mozilla Developer Network or MDN (formerly MDC), is the official reference site for the Mozilla Foundation. The JavaScript section of this site contains a ton of free data regarding the language, its implementation within Mozilla, and other development-related information. Also worthy of perusal are the DOM and CSS sections of the site.
Because of the large size of its community, MooTools has a fair share of developer resources. Here are some of the recommended resources that you should explore:
The Official MooTools Documentation (
http://mootools.net/docs/). This one needs no further introduction. Any serious MooTools developer should have the official documentation site bookmarked.The MooTools Source Repository (
http://github.com/mootools/). A lot of the material in this book wasn't discovered by reading the docs but by reading and examining the MooTools source code. I therefore recommend that you spend some time working with the MooTools source code itself, which is available from the official repositories.The MooTools Forge (
http://mootools.net/forge). The Forge is the official MooTools community plugin and extension resource site. You'll see applications of the information from this book in some of the plugins and extensions published on the Forge, and I advise you to peruse the Forge and examine the published extensions as an exercise in understanding how they use the MooTools API.The MooTorial (
http://mootorial.com) and MooTools 1.3 (http://ryanflorence.com/issue-004/). These two online resources are geared towards MooTools beginners. The first is a little outdated (uses MooTools 1.2), but is still useful in understanding general MooTools development; while the second is a new series that was created for the MooTools 1.3 release.MooTools Essentials by Aaron Newton (2008, Apress), and MooTools 1.2 Beginner's Guide by Jacob Gube and Garrick Cheung (2009, Packt). Like the previous resources, these two are targeted towards MooTools beginners, but in book form. Both are really good introductions to the framework, but they are a little outdated since they still discuss MooTools 1.2.