It's possible to a degree, but only for pages on the same top level domain, and only if you're willing to relax a bit of security by setting `document.domain`.

It's possible to a degree, but only for pages on the same top level domain, and only if you're willing to relax a bit of security by setting `document.domain`. I wrote an ajaxTransport for jQuery to accomplish this exact thing years ago; I can ask about open sourcing it if there's interest since I doubt it's in use anymore since our browser set is IE10+ at this point.