Newbie:Which JS version to learn/Which DOM level?

[Patrick]

Hi

I am currently learning JS from online tutorials and some seem to be
quite old.
Which versions of JS and the DOM shall i focus on and what shall i
skip?
A current tutorial i am going through talks about DOM level 0 and 1
along with IE document.all and NN document.layers proprietary DOM's.
I know JS is at version 1.5 and the DOM level at 2 and 3.

Thanks in advance

Patrick
(e-mail address removed)