CSSHttpRequest is cross-domain AJAX using CSS.

Please see the latest info at http://nb.io/hacks/csshttprequest/

Like JavaScript includes, this works because CSS is not subject to the same-origin policy that affects XMLHttpRequest. CSSHttpRequest functions similarly to JSONP, and is limited to making GET requests. Unlike JSONP, untrusted third-party JavaScript cannot execute in the context of the calling page.

The transport encodes the payload in the background-image property:

#c0 { background: url(data:,Hello%20World!); }

This version has been tested in cross-domain contexts in Safari 3.x, Firefox 3.x and Internet Explorer 6.