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.
This uses prototype to intercept tab focus and place it on a button (or any other element). Firefox and Safari will bypass the button when tabbing through a form. Useful for buttons after textareas.