How to send a cross-document message with HTML?

Create a new web browsing context either by creating new iframe or new window. We can send the data using with postMessage() and it has two arguments. They are as

• message − The message to send
• targetOrigin − Origin name

Let us see an example to send a message from iframe to button:

var iframe = document.querySelector('iframe');
var button = document.querySelector('button');

var clickHandler = function(){
   iframe.contentWindow.postMessage('The message to send.','https://www.tutorialspoint.com);
}
button.addEventListener('click',clickHandler,false);