AJAX and User Controls

Ajax (Asynchronous JavaScript and XML) enables you to update content in a page without posting the page back to the server. Behind the scenes, AJAX uses the XMLHttp ActiveX component (in the case of Microsoft Internet Explorer 6.0) or the XMLHttpRequest intrinsic browser object (in the case of other browsers such as FireFox and Internet Explorer 8.0).

We explore the topic of Ajax in depth in Part IX, “ASP.NET AJAX.” In this section, I want to provide you with a quick sample of using Ajax with a User control. The User control in Listing 7.12 randomly displays one of three quotations. The quotation is updated automatically every 5 seconds (see Figure 7.4).

Figure 7.4. Using AJAX to display a random quotation.

Listing ...

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