I was recently wanting to enable a webpage to utilize some server-side functionality which was on a different server than the one serving the original page. Traditionally, this has been problematic due to browsers' Same origin policy. JSONP is a solution to this problem. Here is how to do it with jQuery...
This webpage can be saved locally to any machine, opened in a browser, and can then load data from my web server:
Here is what the server-side looks like: