Implement the Broadcast Channel API
BroadcastChannel offers a way for all scripts, regardless of window/frame/tab/worker context, to communicate with each other via messaging, similar to MessageChannel.
A message sent via BroadcastChannel is delivered to all environments running with the same origin as the sender.
David Simpson commented
In the meantime, you could try a polyfill:
We want to share data amongst tabs and need this or SharedWorker to correctly implement this.
Andy Earnshaw commented