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At the Forge - Beginning Ajax

Issue 151

From Issue #151
November 2006

Sep 30, 2006  By Reuven M. Lerner
 in
How to put the A (asynchronous) in Ajax.
Conclusion

This month, we finally begin to use Ajax in an application. We see here how it is possible to take some existing JavaScript code and break it apart into two functions: one that invokes the Ajax call and the other that handles the parsing of data when the call receives a response.

However, we also see that there are security and efficiency problems with this approach. A better technique would be to send only the requested user name in the Ajax call and get a simple yes or no answer from the server, indicating whether the user name had been taken already. Next month, we will do just that, using an Ajax POST query instead of our GET query from this month, and replacing usernames.txt with a server-side program that works in conjunction with our Ajax call.

Further Reading

There has been an explosion of books and articles about Ajax programming in the last year, and I am slowly making my way through many of them. Two of the best that I've read are both published by O'Reilly. Head Rush Ajax is aimed at beginners and teaches the introductory material in a fun, effective way. Ajax Design Patterns, which I mentioned earlier in this article, is probably my favorite Ajax book so far (despite its design and editing, which aren't up to the usual O'Reilly standards). This latter book is a good introduction to the subject for experienced Web developers.

The Ajaxian.com Web site has a large number of links, tutorials and articles having to do with Ajax development on a variety of different platforms. If you're interested in Ajax development, it's worth keeping this site in your RSS reader or bookmarks.

Reuven M. Lerner, a longtime Web/database consultant, is a PhD candidate in Learning Sciences at Northwestern University in Evanston, Illinois. He currently lives with his wife and three children in Skokie, Illinois. You can read his Weblog at altneuland.lerner.co.il.

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