Book Image

Learning jQuery - Fourth Edition - Fourth Edition

Book Image

Learning jQuery - Fourth Edition - Fourth Edition

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
Credits
Foreword
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Event delegation


Recall that to implement event delegation by hand, we check the target property of the event object to see if it matches the element that we want to trigger the behavior. The event target represents the innermost, or most deeply nested, element that is receiving the event. With our sample HTML this time, however, we're presented with a new challenge. The <div class="photo"> elements are unlikely to be the event target since they contain other elements, such as the image itself and the image details.

What we need is the .closest() method, which works its way up the DOM from parent to parent until it finds an element that matches a given selector expression. If no elements are found, it acts like any other DOM traversal method, returning a new empty jQuery object. We can use .closest() to find <div class="photo"> from any element it contains as follows:

// Unfinished code
$(document).ready(function() {
  $('#gallery').on('mouseover mouseout', function(event) {...