File upload from S7G2 Web Server to PC Browser

I have a Web Server running on our custom S7G2 board using the GT202 module.

I want to be able to upload a file using HTTP from the S7G2 board (Server) to my Chrome browser (Client)

The file will probably go into the downloads directory.

The user will click on a button on the PC screen, which I will catch on my Server code, but then the Server needs to start the download and the Chrome Server should accept it.

Any ideas on the functions I should use to achieve this ?

thanks,

alan..