Beginning XML, 5th Edition

Chapter 16

AJAX

WHAT YOU WILL LEARN IN THIS CHAPTER:

• What AJAX is used for
• How to use AJAX
• When to use JSON, HTML, or XML with AJAX
• How to generate JSON on the web server
• Web architecture, REST, and best practices

AJAX stands for Asynchronous JavaScript And XML, but the term refers to a way of writing web-based applications that are responsive and give a fast, positive user experience by leveraging the fact that the web server can be working at the same time as the client computer running the web browser. The trick that AJAX enables is to update parts of the current web page without having to reload the entire page. The extra interactivity this allows, combined with big shiny buttons and a particularly fashionable sort of color scheme, is known as Web 2.0. The biggest challenge, as you’ll learn, is to create web applications that are accessible to people regardless of their needs and abilities, and that fit in with the web architecture of links and bookmarks. In this chapter you’ll learn how AJAX works (including the JavaScript part) and you’ll make a working AJAX-based web page so you can see how AJAX and XML fit together.

AJAX OVERVIEW

The AJAX pattern has several uses. This section first describes the situations in which you use AJAX, and then goes into detail about what it really is and how it works. The short description is that AJAX is a way for a web page to use the JavaScript language to fetch data quietly in the background without any need for the web page to reload ...