I don't see any flaws in the technique, and its a very cool technique. But one problem I see is that you have to have the responding server package the data cor

I don't see any flaws in the technique, and its a very cool technique. But one problem I see is that you have to have the responding server package the data correctly for transport via this method. Meanwhile, doing JSONP simply requires the data on the 3rd party server be delivered in a JSON format, while this requires the special 2kb packaging. Its definitely a more secure way of obtaining remote data from untrusted 3rd parties, but the trade-off is that the 3rd party has to be setup to correctly deliver the data.