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

Using the jqXHR object


When an Ajax request is made, jQuery determines the best mechanism available for retrieving the data. This transport could be the standard XMLHttpRequest object, the Microsoft ActiveX XMLHTTP object or a <script> tag.

Because the transport used can vary from request to request, we need a common interface in order to interact with the communication. The jqXHR object provides this interface for us: it is a wrapper for the XMLHttpRequest object when that transport is used, and in other cases, it simulates XMLHttpRequest as best it can. Among the properties and methods it exposes are:

  • .responseText or .responseXML containing the returned data

  • .status and .statusText containing a status code and description

  • .setRequestHeader() to manipulate the HTTP headers sent with the request

  • .abort() to prematurely halt the transaction

This jqXHR object is returned from all the jQuery's Ajax methods, so we can store the result if we need access to any of these properties or methods...