On Closures and the Module Pattern
Everything you need to know about closures and the JS module pattern (this article is quite useful if you're ever using jQuery
Google Chrome Developer Tools Keyboard Shortcuts
I'm in the process of making the switch from Firebug to Chrome. Firebug is a very, very good tool and has probably had the most impact on me as a developer compared to all of the other tools I've used, so I feel a little bad for leaving Firebug.
The base Firebug was OK, and the debugging interface was relatively simple. What I really enjoyed about Firebug were the extensions, like FireQuery (which would highlight DOM elements with jQuery event listeners attached) and FirePhp (which would pipe messages from XDebug into the Firebug console).
However, nowadays everyone is using Google Chrome's dev tools, so I might as well too. I'm still trying to figure them out, and I'm sure I'll be using more of the panels (such as Resources) in the future. And we all know that the first step in getting good at a tool is learning the keyboard shortcuts:
The mysteries of
The MDN documentation is still the best I've found
JSLint Will Change Your Life!!
Seriously. Here's a good Vim plugin: