Broadcast messages for Chrome Extensions

Why?

Sometimes you need to receive messages sent by chrome.runtime.sendMessage in the sender's frame, so you have something like this in your extesion page's js file:

chrome.runtime.onMessage(function(message) {
  ...
});

...

chrome.runtime.sendMessage(...);

But Chrome behaviour for this among versions and even inside a single version is inconsistent:

• up to 57 onMessage listener within one frame will be triggered only if there are at least two extension's frames(chrome.extension.getViews().length > 1)
• in versions from 57 onMessage is not triggered within one frame in any case. It is the expected behaviour.

For further reading see:

• https://bugs.chromium.org/p/chromium/issues/detail?id=677692
• https://bugzilla.mozilla.org/show_bug.cgi?id=1286124#c35

Usage

Just include broadcaster.js in your addon and replace:

• chrome.runtime.sendMessage by Broadcaster.sendMessage
• chrome.runtime.onMessage by Broadcaster.onMessage

Sending message:

// simple
Broadcaster.sendMessage({"message": 1});

// with callback
Broadcaster.sendMessage({"message": 1}, function(response) {
});

Receiving message:

Broadcaster.onMessage.addListener(function(message, sender, sendResponse) {

});