Wiktor Zychla has assembled a tiny AJAX framework contest between Visaul WebGui, ASP.NET AJAX and Ajaxium. Comparing a givven scenario he checked bandwidth consumption, requests per second, etc. The results as Wiktor wrote them are: "The VWG is an undoubt winner. It did a great job of serving the highest number of requests per second, 422, and is also a clear winner regarding the amount of data sent to and from the server."
More than two years ago we've built a small web application used to collect and print documents required to participate in secondary school final examinations in Poland. The application is used quite extensively by people from all over the country.
The application, maturzysta.vulcan.pl, is located here.
From the web developer's point of view there is one interesting aspect of the main form of the application: there are about 30 dropdown lists with complicated logic between their selections: when you change the selection in one list, few others should be cleared or repopulated with context-bound data. There is also quite a lot of validation of various dependencies between user's selections.
The first version of the application was built as a server-side application: all SelectedIndexChanged events were auto-postbacked and processed on the application server. This caused a lot of trouble since the heavy form had to be sent to and fro the server.
In the meantime, few promising AJAX frameworks appeared and we thought that it would be possible to go back to the initial version of the application but instead of expensive postbacks we could take the AJAX approach and replace postbacks with callbacks. This could solve all problems: reduce the traffic and still keep the application logic on the server-side.