Chrome extensions communication (content scripts)

Question

I got 2 extensions in Chrome, both only uses content scripts at the moment. Both extensions listen on websocket for messages from the server. Also they both get the same message "same" (obviously a minimal difference) time. After they got the message they both process it and at the end they both have a result which is an int number.

What I would like to do is sending this number from extension A to extension B and from ext. A to ext. B so they both have the other's result.

I've really tried to google a solution for this, but I couldn't find any. Also I would like to avoid sending the results back to the server and then back to the extensions again.

Is there any way (preferably only JS) to do this?

Thanks!

Answer 1

This has been discussed here: Can Chrome extensions communicate with each other?

you can use this api: https://developer.chrome.com/extensions/messaging#external

chrome.runtime.sendMessage(otherExtensionId, {msg: 'hello'},
  function(response) {
    if (response.msg='hi')
      chrome.runtime.sendMessage(otherExtensionId, {msg: 'how are you?'});
  });

and in the other extension:

chrome.runtime.onMessageExternal.addListener(
  function(request, sender, sendResponse) {
    if (request.msg=='hello') {
      sendResponse({msg: 'hi'});
    }else ifif (request.msg=='how are you?'){
      doSomething()
    }
});

also for another means of communication, you can create an invisible div inside your page, and have both extensions constantly checking if it's contents change.