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Rob Cameron and Dale Michalk

"Pro ASP.NET 3.5 Server Controls and AJAX Components"

axd handler
without the extra deployment step of copying loose file content.
??? Using ASP.NET 2.0 (or later) client callbacks: A new feature introduced in ASP.NET 2.0
provides a structured way for client-side scripts to invoke server-side functionality to
retrieve data or content from the server without executing a full-page postback and refresh
of the HTML page in the browser.
We feel the best way to cover these client-side script scenarios is to develop a set of server
controls that demonstrates the listed capabilities. The controls we build in this chapter include
an image control that performs client-side image mouse rollovers, a control that confirms the
user??™s action when clicking a link button, and an up/down numeric control similar to its desktop
cousin that can work with or without JavaScript support. In the last example, we show how to
use client callbacks as part of a server control that fetches data from an MSN Money stock news
feed without requiring a postback when the requested stock symbol is changed by the user.
Handling Client-Side Events
The web browser has its own object model representing the HTML tags and events that occur
when the user is interacting with them. This event system within the browser has been around
for a while and is completely different from the server-side event mechanism we discussed in
detail in Chapter 5.


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