Programming Atlas

Chapter 16. Other Ajax Tools

Although Atlas is loaded with features that make it easy for you to work with Ajax technologies, it does require ASP.NET Version 2.0 and, more important, it is not yet considered stable, although there is a Go Live license available for sites that want to start using it today. The final release is expected to ship with the next versions of ASP.NET (3.0) and Visual Studio (code-named Orcas). Most analysts expect that both will be released in 2007, so there is some reason to be reluctant to deploy Atlas-based applications now. History has shown that Microsoft’s beta versions that came with a Go Live license do not differ too much from the final versions, at least in terms of backward compatibility to prerelease versions. But time will tell what the next iterations of Atlas will bring.

So if you like the Ajax way of doing things, but don’t feel ready to commit to Atlas, this chapter offers some other approaches for exchanging data with the server without a page refresh. Some require ASP.NET 2.0, whereas others work with ASP.NET 1.1.

Client Callbacks

Contrary to popular belief, ASP.NET 2.0 does include built-in support for Ajax. Well, at least in a limited way. Rather than calling it Ajax, however, Microsoft refers to this ASP.NET 2.0 technology as client callbacks. Client callbacks enable ASP.NET web applications to implement asynchronous calls to the server using JavaScript: one built-in JavaScript function requests data and another fetches ...