Ajax – as you will discover shortly – is not a new technology. Rather, it is a combination of standards that makes it possible to realize the rich potential functionality of current Web browsers. Perhaps the key defining feature of Ajax-enabled Web applications is the ability for the Web browser to communicate with the Web server in out-of-band operations; this is known as asynchronous, or partial-page, posts. In practice, this means that the user can interact with server-side functionality and data without needing a full-page refresh. For example, when a link is followed to move to the second page of data in a table, Ajax makes it possible to refresh just the table’s content rather than the entire Web page. This means that there is less staff is required across the Internet, which leads to a more responsive Web application. You will see this example in practice later in this chapter, as well as many more examples that illustrate the power of Ajax in Web applications.
You will be using Microsoft’s implementation of Ajax in the code in this chapter, known as ASP. NET AJAX. This implementation takes the Ajax model and applies it to the ·ASP.NET framework. ASP.NET AJAX provides a number of server controls and client-side techniques that are specifically targeted at ASP.NET developers” and that enable you to add Ajax functionality to your Web applications with surprisingly littleeffort,
This chapter is organized as follows:
- First, you learn more about Ajax and the technologies that make Ajax possible.
- Next, you learn about ASP.NET AJAX and its component parts, as well as the functionality that ASP.NET AJAX offers.
- Last, you see how to use ASP.NET AJAX in your Web applications, by using both server-side and client-side code.