Persistent data between different games - local save for WebGL

I want user A to save data from WebGL game G1 and load the same data in WebGL game G2. No server or other computer would be aware of that. However, Application.persistentDataPath returns a path that it’s end directory is project specific.

How can I save data in one game in WebGL to be loaded in another WebGL game?

Edit - To clarify, the desired solution I need is exactly what the web series Mardrek RPG.

Use the WWW class.