I have played a little with AJAX library part of visual studio 2008.  But hey do someone know how to easily modify this library and/or replace it by  its own, sorry I didn't  find yet that in the various project property setting...  I see that you have to use it, it probably send part of any http request just what it needs on the client to work, but what if someone want to add trace into that library...yeah there is surely something i have missed somewhere.

By the same time I have tried the javascript debugger. Looks like very funny. Just to first see the browser global object like the DOM exposing the entire document, very interesting.