Javascript is an asynchronous languaje, as soon as you learn how to take advantaje of that you would have a better understaning of javascript. So my recomendation, is to learn Ajax as soon as posible.
Using jQuery is a great way to do it because it that the problem of browser compatibility.
To be fair, http://mrdoob.com has a lot of flash in the examples. You can learn http://processing.org/ and export to canvas if you want to do things like the stuff on that page.