Introduction

There are a lot of common tasks that need to be performed when writing JavaScript. A large proportion of this simply involves dealing with differences between web browsers. The need for a way to hide or abstract the specifics of each browser into a standard interface gave rise to sets of tools known as JavaScript libraries. One of the leading libraries in use on the web today is the Yahoo! User Interface Library (YUI).

Moodle includes a copy of the YUI as its preferred JavaScript library. YUI provides developers with access to a wide range of tools for enhancing their web applications:

The YUI Library is a set of utilities and controls, written with JavaScript and CSS, for building richly interactive web applications using techniques such as DOM scripting, DHTML and AJAX. YUI is available under a BSD license and is free for all uses. YUI is proven, scalable, fast, and robust. Built by frontend engineers at Yahoo! and contributors from around the world, it's an industrial-strength...