http://devel.oping.net/content/client-side-datasets-with-ajax-net.aspx
Everybody loves .NET’s DataSets. They provide the most simple yet powerful way to manipulate in-memory tables and data collections on the server-side.
Good news for hardcore AJAX web developers: using Michael Schwarz’s amazing Ajax.NET Professional library we can unleash the power of server-side DataSets to the client-side using Javascript. Not only that, but we can create a DataSet and populate it on the server, invoke it on the client side, modify it or create a new one and send it back to the server.
To get things clearer, i recommend to check first the online demo wich implements the code discussed in this article.