as described here : http://www.mail-archive.com/jquery-en%40googlegroups.com/msg13093.html
Andy Martone Tue, 31 Jul 2007 14:10:30 -0700
I've come across some strange behavior in IE7. Sometimes when an
XmlHttpRequest receives a 204 (No Content) HTTP status code on the
response, IE sets the XmlHttpRequest object's status property to
1223. In my code, this seems to be happening when my server is
returning a 204 from a PUT request - IE seems to be handling the 204
from a DELETE request okay.
Note that I've seen this also on IE6.
(Also there is no component for 'Ajax' ).
Attached is a patch to fix it.
