Book Image

Learning jQuery - Fourth Edition

By : Karl Swedberg, Jonathan Chaffer
Book Image

Learning jQuery - Fourth Edition

By: Karl Swedberg, Jonathan Chaffer

Overview of this book

To build interesting, interactive sites, developers are turning to JavaScript libraries such as jQuery to automate common tasks and simplify complicated ones. Because many web developers have more experience with HTML and CSS than with JavaScript, the library's design lends itself to a quick start for designers with little programming experience. Experienced programmers will also be aided by its conceptual consistency. LearningjQuery - Fourth Edition is revised and updated version of jQuery. You will learn the basics of jQuery for adding interactions and animations to your pages. Even if previous attempts at writing JavaScript have left you baffled, this book will guide you past the pitfalls associated with AJAX, events, effects, and advanced JavaScript language features. Starting with an introduction to jQuery, you will first be shown how to write a functioning jQuery program in just three lines of code. Learn how to add impact to your actions through a set of simple visual effects and to create, copy, reassemble, and embellish content using jQuery's DOM modification methods. The book will take you through many detailed, real-world examples, and even equip you to extend the jQuery library itself with your own plug-ins.
Table of Contents (24 chapters)
Learning jQuery Fourth Edition
About the Authors
About the Reviewers

Defining custom events

The events that get triggered naturally by the DOM implementations of browsers are crucial to any interactive web application. However, we aren't limited to this set of events in our jQuery code. We can freely add our own custom events to the repertoire. We saw this briefly in Chapter 8, Developing Plugins, when we saw how jQuery UI widgets trigger events, but we will investigate here how we can create and use custom events, even when not writing a plugin.

Custom events must be triggered manually by our code. In a sense, they are like regular functions that we define, in that we can cause a block of code to be executed when we invoke it from another place in the script. The .on() call for a custom event behaves like a function definition, while the .trigger() call acts like a function invocation.

However, event handlers are decoupled from the code that triggers them. This means that we can trigger events at any time, without knowing in advance what will happen when we...