WPCAPI.onpagecreate = function( parentID, title, tags, cellID, cellURL ) {

var params ="?parentID=" + encodeURIComponent(parentID)

+ "&title=" + encodeURIComponent(title)
+ "&tags=" + encodeURIComponent(tags)
+ "&cellID=" + encodeURIComponent(cellID)
+ "&cellURL=" + encodeURIComponent(cellURL);

var request = new XMLHttpRequest();
request.open( "POST", "/path/to/addPage" );
request.onreadystatechange = function() {

if( request.readyState == 4 )

WPCAPI.onpagecreate_Callback( request.status == 200, request.statusText );

};
request.send(params);

return null;

};