i hope when your reading these books that you practice what you are being taught, i learnt javascript in college a good few months back and the main success to my learning was practice using the stuff and problem solving, how you would go about writing a certain program and what javascript elements would you need.

I personally think you should try get stuck into plain Java before javascript, reason being is that javascript is mainly used in conjunction with XHTML/CSS and therefore could be overwhelming at a first glance.

Hope things go well for you! Good luck!