Two way communication between the browsing contexts in HTML5

Two-way communication between the browsing contexts is called channel messaging. It is useful for communication across multiple origins.

While creating messageChannel, it internally creates two ports to send the data and forwarded to another browsing context.

• postMessage() − Post the message throw channel
• start() − It sends the data
• close() − it close the ports

In this scenario, we are sending the data from one iframe to another iframe. Here we are invoking the data in function and passing the data to DOM.

var loadHandler = function(){
   var mc, portMessageHandler;
   mc = new MessageChannel();
   window.parent.postMessage('documentAHasLoaded','https://foo.example',[mc.port2]);
   portMessageHandler = function(portMsgEvent){
      alert( portMsgEvent.data );
   }
   mc.port1.addEventListener('message', portMessageHandler, false);
   mc.port1.start();
}
window.addEventListener('DOMContentLoaded', loadHandler, false);