Same method can be used to update the originating Excel file on server by passing url parameter to it.
This method posts pq_data, pq_ext, pq_decode, pq_filename parameters to the server.
Server script can copy data from pq_data and base64 decode the data if pq_decode is true, save data in a file and replace the originating excel file with it.
Note that file based exports ( xlsx, html, json, csv ) don't support incremental or differential updates.