As described in JSON and JSONP, JSONP provides a way to connect the browser of the user with AFS acp front end even when they are not directly communicating (for example, when a web portal relays user queries).
A JSONP call must specify a document element and a method. The resulting output feed is made by surrounding the JSON output feed by a call to the method of the element.
For example, when acp is called with afs:output=application/antidot-suggestions+jsonp;method=element.process, the JSONP output feed may be:
element.process([ "query" , ["completion1", "completion2"…] ])