You don't have to memorise every obscure part of the JavaScript language and you don't need to memorise all the ways of combining JavaScript commands together to achieve various results. All you really need is a general knowledge of JavaScript and an appropriate JavaScript book that you can use to look up the solutions to your problems.
JavaScript the Definitive Guide
One of the most complete references to everything that can be done with JavaScript.
JavaScript - The Good Parts
This book goes into detail on what parts of the JavaScript language you should be using and what parts the language would be better without.
The Art & Science of JavaScript
This book covers a small number of specific tasks that you may want to have in your web page and shows you how to properly achieve them using modern JavaScript.
JavaScript and DHTML Cookbook
Need to know the JavaScript code to perform any of a whole range of tasks? Well this book is filled with a long list of things you may want to do with JavaScript along with sample code that does them.
Dynamic HTML the Definitive Reference
Dynamic HTML (or DHTML) was a popular term for the combination of HTML and JavaScript using the DOM to incorporate interactive effects into web pages. This book is a reference to many of these effects and how to achieve them.
