When Gentics Portal.Node receives an AJAX enabled request, the response will be a JSON object with a specified layout, see “Response Format of AJAX enabled requests API” (Section 6.3.1) for the detailed documentation of this API.
This response may include the request to replace a portlet in the browsers DOM tree with a new content. This request (client-side function call) is specified in “Replace rendered portlets API” (Section 6.3.3.3.3) .