JSONP (or JSON with Padding) is a technique used by web developers to overcome the cross-domain restrictions imposed by browsers to allow data to be retrieved from systems other than the one the page was served by.
French Geoportal resources access library
French Geoportal Extensions for OpenLayers (test)
French Geoportal SDK based on OpenLayers (2D)
French Geoportal SDK based on OpenLayers (2D) and iTowns (3D) libraries
French Geoportal Extensions for iTowns (test)