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.
i found this snippet here on snipplr (see the link up above), and really liked it. it came up with a validation error under XHTML 1.0 Strict so i changed it to what you see in the bottom.....
Useful, but you need a semicolon in line 4