How do I send object (like json string) to web server?

Hello;

How do I upload a json string to the web server? The same server I started the game from? I just want to send a text string up and call the file TryOne.txt on the server. Do I use AJAX for this?

How do I get it back off the server and into the game? I don't want anything complicated, just a simple string transfer to and from the server. Same file name on the server both ways, same string both ways.

thanks for your time.

yours

Winkr7