Add web interface to an embedded QT application

I have an embedded board that runs a Qt application (developed by me, I have the source code), this app is always active and it doesn't have any GUI (no display!), I'd like to add a web page that works as monitor (show some simple values) and permit to configure some parameters for the application... The first goal would be a simple web-page that permit to set a variable in the application, and show the status of another variable in "realtime".

The board is an ARM ,runs Linux and a web server is available, i already used succesfully cgi and php...

How i can communicate between the web part and the process of the application? I can use cgi to call another app that communicates to the main application with a socket, but i think there are better solutions...

browsing the web i think the keywords are Json-Ajax-JQuery but i don't find any example useful for my case.

Thanks for any advise and/or example