[jQuery] Re: jQuery form plugin and document.domain failure

[Dave Methvin]

.ajaxForm uses $.ajax, which uses XMLHttpRequest. There are some
issues with the way xhr interacts with document.domain, independent of
jQuery.

http://fettig.net/weblog/2005/11/28/how-to-make-xmlhttprequest-connections-to-another-server-in-your-domain/