Send messages between open pages or tabs in same browser
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sysend.js is small library that allow to send message between pages that are open in the same browser. It also support Cross-Domain comunication. The library don't use any dependencies and use HTML5 LocalStorage API or BroadcastChannel API. If your browser don't support BroadcastChannel (see Can I Use) then you can send any object that can be serialized to JSON with BroadcastChannel you can send any object (it will not be serialized to string). You can also send empty notification.

Tested on:

GNU/Linux: in Chromium 34, FireFox 29, Opera 12.16 (64bit)
Windows 10 64bit: in IE11 and Edge 38, Chrome 56, Firefox 51
MacOS X El Captain: Safari 9, Chrome 56, Firefox 51


Include sysend.js file in your html, you can grab the file from npm:

npm install sysend

or bower

bower install sysend

you can also get it from CDN:


window.onload = function() {
    sysend.on('foo', function(message) {
    var input = document.getElementsByTagName('input')[0];
    document.getElementsByTagName('button')[0].onclick = function() {
        sysend.broadcast('foo', {message: input.value});

If you want to add support for Cross-Domain communiation you need to call proxy method with target domain:


on firefox you need to add CORS for the iframe (see Cross-Domain LocalStorage)


Open this demo page in two tabs/windows.


sysend object:

  • on(name, callback) - callback(object, name) - add event of specified name
  • off(name [, callback]) - remove callback
  • broadcast(name [, object]) - send object and fire all events with specified name (in different pages that register callback using on). You can also just send notification without object
  • proxy(url) - create iframe proxy for different domain, the targer domain/url should have proxy.html file. If url domain is the same as page domain, it's ignored. So you can put both proxy calls on both domains (new in 1.3.0)


Copyright (C) 2014-2018 Jakub Jankiewicz
Released under the MIT license

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.