Send messages accross windows using a simple API

Usage no npm install needed!

<script type="module">
  import postmessagePlus from '';


postmessage-plus Build Status

Simple postmessage library. Provides a common API for interacting the window.postMessage and security against listening to dangerous messages.

Generally, window communications take the form of a client/server interaction. The client window sends messages to the server. The server listens to one or more client's messages.

postmessage-plus supports client-server as well as client-client interactions.

How to use

Here is a standard setup


// Create an instance
var pm = new PMPlus({
  listenDomain: '' // string, array or regex

// Listen to a channel
pm.listen('myChannel', function(data, respond) {
  //... do something async or sync
    true,  // true for success, false for error
    'Got your message' // Response or Error


// Create an instance
var pm = new PMPlus({
  sendDomain: '' 
  // only string allowed, default that can be changed on individual messages

// Send a message
  w: iframe.contentWindow // window reference
  channel: 'myChannel',
  data: 'Here you go',
  callback: function(success, info) {
    if(success) {
      console.log('Sucess: ', info);
    } else {
      console.log('Error: ', info);

A single window can be both a server and a client. To send and receive messages, use sendDomain and listenDomain.