Question

What is the best way to share data between open tabs in a browser?

Answer 1

For a more modern solution check out this answer quoted below:

I’m sticking to the shared local data solution mentioned in the question using localStorage. It seems to be the best solution in terms of reliability, efficiency, and browser compatibility.

localStorage is implemented in all modern browsers.

The storage event fires when other tabs makes changes to localStorage. This is quite handy for communication purposes.

Reference:
https://developer.mozilla.org/docs/Web/API/Web_Storage_API