Yahoo has a great set of videos about JS: http://developer.yahoo.com/yui/theater/

The ones by Douglas Crockford — “The JavaScript Programming Language”, “An Inconvenient API: The Theory of the DOM”, and “Advanced JavaScript” — are intended to be watched in that order, but I think watching the DOM one first helps to clarify what happens in the browser when JS is run.

btw, Yahoo Video has no rewind/forward capability, so you might want to download the slides as well (linked next to each video).