A loading image is shown as a progress indication when an AJAX request is performed, i.e. when the page is loading silently. This improves the look and feel of the page as there are no sudden changes and unnecessary flickering.

The example demonstrates all present loading images coming with the ajax controls.

You can set your own picture as a loading image, just show the path to it in the loading panel definition:

This example illustrates how easy it is to AJAX-enable an asp.net control. By simply wrapping a standard (or custom) control in a RadAjaxPanel, all postbacks that it performs will be converted to an AJAX requests without writing a single line of code. All events handlers, viewstate and form data are preserved and the page life cycle goes on as normal. We have chosen two relatively complex controls: a Calendar and a Grid and have wrapped them in RadAjaxPanel to demonstrate how to "ajaxify" them.

This is a demonstration of an AJAX powered progressbar to monitor file uploads with (Cake)PHP. Yes you've heard right! Well, but before you begin to drool all over the place, there is one downside: it requires a Perl script that allows you to know the upload progress. But besides this little downer you have a maximum of flexibility regarding the design of your progress-bar and integration in your system.

So you now understand Ajax and have a basic idea about the XMLHttpRequest object and how to create it. If you've read closely, you even realize that it's the JavaScript technology that talks to any Web application on the server rather than your HTML form being submitted to that application directly.

What's the missing piece? How to actually use XMLHttpRequest. Since this is critical code that you'll use in some form in every Ajax application you write, take a quick tour through what a basic request/response model with Ajax looks like