ASP.NET AJAX

Introduction

ASP.NET AJAX enables you to create Web pages that are more interactive and more responsive to user input than pages that are created exclusively with server-based elements. ASP.NET AJAX includes both client ECMAScript (JavaScript) libraries and ASP.NET server controls.

For ASP.NET AJAX, the ASP.NET 3.5 Extensions Preview release enables you add entries to a browser's history stack that are linked to a specific state of a Web page, such as the state created by an asynchronous postback.

Browser History (Back Button Support)

An AJAX-style Web page can interact with the server by using asynchronous requests. This enables users to perform many tasks without navigating away from the Web page, and it makes the Web application feel more like a locally installed application.

When users click the browser's Back button, they might expect to return the Web application to a previous state (for example, the state before the most recent asynchronous postback). By default the browser unloads the page completely and returns to the previous Web page, independent from any asynchronous requests. Frequently, this is not what the user intended.

An AJAX-style page can also involve browser-based (client) interaction without any server interaction. As with asynchronous postbacks, these actions might cause changes in the application that logically are places where users want to return when they click the Back button.

In these cases, you can manage browser history, and by extension the Back and Forward button navigation, to provide a more logical and natural navigation model in your Web application. As the page developer, you can control the state that is required to re-create the page. You can manage history navigation in both server and client code. You do this by defining points in your application that behave like bookmarks, referred to as history points, that users return to when they navigate with the Back and Forward buttons.

Topics in this Section

Managing Browser History Using Server Controls

Managing Browser History Using Client Script

Related Sections

ASP.NET AJAX API

This topic is ASP.NET 3.5 Extensions pre-release documentation and is unsupported by Microsoft. Blank topics are included as placeholders and existing content is subject to change in future releases. To provide feedback or ask questions about the release, please go to the ASP.NET 3.5 Extensions forums.