Updating web pages with ajax
Enabling partial rendering with this default page is as simple as revisiting Step 10 of this walkthrough and dropping controls onto the page.Markup-Enabled Properties: Quite simply, the above script registers a callback with the client-side AJAX runtime for when the asynchronous request has been completed.Consider a form that, among other things, has a postal code textbox which is supposed to populate a city and state field on a form or control.This form ultimately collects membership information, including a user's name, address, and contact information. NET AJAX Extensions is the ability to do a partial or incremental page updates without doing a full postback to the server, with no code changes and minimal markup changes.The advantages are extensive – the state of your multimedia (such as Adobe Flash or Windows Media) is unchanged, bandwidth costs are reduced, and the client does not experience the flicker usually associated with a postback. NET technology brings an object-oriented and event-driven programming model and unites it with the benefits of compiled code.By doing so, you can inject an Update Panel between the control's children and the outside world if you determine the page supports partial rendering; otherwise, you can simply layer the child controls into a container instance.
The Script Manager control provides extensive support for localization of script strings and user interface components; however, that topic is outside of the scope of this whitepaper.
For more information, see the whitepaper, Globalization Support in ASP. Markup-Enabled Properties: control is the control that delimits the server-side content that will take part in the partial rendering functionality of the AJAX Extensions.
There is no limit to the number of Update Panel controls that can be on a page, and they can be nested.
The entire control was wrapped within an Update Panel and dropped onto a Web Form.
When the postal code is entered by the user, the Update Panel detects the event (the corresponding Text Changed event in the back-end, either by specifying triggers or by using the Children As Triggers property set to true).