This is a new kind of JavaScript book. It's not cut'n'paste, it's not a reference, and it's not an exhaustive investigation of the JavaScript language. It is about client-side, web-focused, and task-oriented JavaScript. 'Practical JavaScript for the Usable Web' takes a two pronged approach to learning the JavaScript that you need to get your work done: teaching the core client-side JavaScript that you need to incorporate usable interactivity into your web applications, including many short functional scripts, and building up a complete application with shopping cart functionality.