I have spent a few days researching on any new solutions of cross-site scripting. The technologies have not changed much since 1999. I still remeber the desktop.com that implemented the whole thing in a browser. The XmlHttpRequest commonly used today in Ajax can not be used in cross-site due to security restriction imposed by browser. The next one is IFrame. The third one is to use Script tag that loads JSON.

Script returning JSON is good for communicating data between two sites, but it requires additional work to render UI in JavaScript based on JSON data.

It will probably take a few years before a new standard for cross-site Java-scripting emerges and becomes widely adopted. Until then meshing up web applications and services from different sites will be limited and inefficient.