I wonder if Ballmer is aware that Elijah is pumping FF as his first-target JS environment on an MSDN blog? Not exactly eating your own dog food.
...with the sub-text being: develop on FF (best tools)... all other browsers are roughly compliant... except for IE, which needs additional testing. Ouch.
Kudos to Microsoft for indirectly recommending Firefox!
The FireBug console with FireQuery installed will also highlight any DOM elements that match your selector when you mouse over the results in the console. I hadn't heard of FireFind before this; I'm gonna have to give it a try.
I'm glad there is finally a decent article on how to use / debug jquery and firebug. I've been waiting for one of these for years now. /sarcasm_off