Pro JavaScript Techniques
Pro JavaScript Techniques is the ultimate JavaScript book for the modern web developer. It provides everything you need to know about modern JavaScript, and shows what JavaScript can do for your web sites. This book doesn't waste any time looking at things you already know, like basic syntax and structures.
The unobtrusive version requires an onload statement. Doing that in a backward-compatible fashion can be a pain in the ass. So here is an inline version for use with older code. This should work "out of the box" with any browser that has javascript.