I would like to know if jQuery 1.5.X truly has cross-domain. I was unable to find sufficient documentation on the site and my own cross-domain tests did not work either. I am not talking about JSONP but any regular call (xml, html, json).
I do not see how jQuery can circumvent browser restrictions without use of Adobe Flash/proxy etc.
If the browser supports CORS you can directly use jQuery's AJAX methods to send a cross-domain AJAX request.
Unfortunately IE uses a different method which is not supported by jQuery (yet?).