Other domains / servers need to support JSONP, which basically wraps JSON in the callback.
In jQuery, the call would look like this:
$.getJSON(
'http://otherdomain.com/api/whatever?callback=?',
{ key: 'value', otherkey: true },
function(data){
}
);
The actual response from another server (if you looked at what is actually being sent) would look like this:
http:
the_callback_function_name({ "json": "data here"});
jQuery getJSON JSONP callback=?. , , json_callback=?. , URL- callback: '?' data getJSON.