AJAX Widget Framework

[Laszlo Nagy]

I'm looking for an open source, AJAX based widget/windowing framework. 
Here is what I need:

- end user opens up a browser, points it to a URL, logs in
- on the server site, sits my application, creating a new session for 
each user that is logged in
- on the server site, I create windows(frames), put widgets on them, 
write event handlers etc. Just like with wx or pygtk.
- However, windows are created in the user's browser, and events are 
triggered by Javascript, and sent back to server through AJAX.
- the server side would be - of course - written in Python.

I was looking these projects:

http://www.uize.com/
http://pyjs.org/

There are many frameworks listed here which I did not check: 
http://internetmindmap.com/javascript_frameworks. I have no idea which 
has Python support, and probably there are only a few that worth looking 
at. I wonder if you could tell me which are the pros and contras for 
these frameworks. If there is a comparison available on the NET, 
pointing me to the right URL would help a lot.

The bottom line...

My main goal is to develop enterprise class OLTP database applications. 
I'll need grid widget to display data in tabular format, and I'll use 
events heavily for data manipulation, live search, tooltips etc. I'm 
familiar with wxWidgets, pygtk and other toolkits, but not with AJAX. I 
have never used a system like that.

Thank you,

   Laszlo