A practical walkthrough of using map/reduce with MongoDB to aggregate statistics for generating a report.
A clever hands-on interactive mini-course by Nathan Whitehead that guides you through bite-sized chunks from variables, to functions, to return values, to functions as first-class objects and right into closures and finally continuations. The hands-on exercises are JS Linted and unit-tested which gives you ample space to try out your new-found knowledge.
Remy Sharp dissects a piece of jQuery code pointing out the red flags. Each flag is taken in turn, explained and shown how to correct. Takes into account context and the flexibility of jQuery
Tim Huegdon uses JavaScript to fix Safari's bug where clicking on a label doesn't set focus to the corresponding field element (a useful accessibility aid). Using YUI and event delegation Tim walks us through the development of this piece of code involving attaching an event listener, getting the target of an event, then finding the field that corresponds to the label, and focusing on it if its a text field, or activating / selecting the form element if its a radio button or checkbox.
An online copy of O'Reilly's 2002 book Creating Applications with Mozilla. It focused on pre-1.0 versions of Mozilla, so details about the application structure has changed, but the XUL elements are relatively stable.
Christian Heilmann's excellent guide to writing unobtrusive JavaScript. Takes the reader from the inline JavaScript world right through to a clean dynamically attached events with all the JavaScript code in external files. Covers DOM Scripting. This is the key reference to unobtrusive scripting.
Dustin Diaz discusses the Object Literal form of JavaScript, pointing out benefits such as better organisation of code in a namespace / wrapper.
Mark Pilgrim's essential online book about developing Greasemonkey scripts. Excellent starting point for Greasemonkey developers. Covers everything from setting up a Greasemonkey scripts to common DOM coding idioms, as well as a brief rundown of XPath, and case studies of Greasemonkey scripts.