When I first set out to learn JavaScript, I had two books with me:
1.) Learning JavaScript by Shelley Powers
2.) DOM Scripting: Web Design with JavaScript and the Document Object Model by Jeremy Keith
I found Learning JavaScript too dense so I put it down for awhile and picked up DOM Scripting, and I'm glad I did.
I thought DOM Scripting was very understandable and it also explains JavaScript best practices, such as unobtrusive JavaScript and graceful degradation.
Later on, I went back to Learning JavaScript which helped me understand some of the more advanced uses of JavaScript, such as AJAX.
So, I would recommend starting with DOM Scripting and then moving onto Learning JavaScript.
Nick
