JSFiddle - React, Tailwind, and code Playground

HTML

<iframe src="javascript:void(0);"/>

JavaScript

var myFrame = document.getElementsByTagName('iframe')[0];

myFrame.addEventListener('load', function () { // add a listener
    console.log('<iframe> loaded\n', myFrame.contentWindow, myFrame.contentDocument, '\n', myFrame.contentDocument.body.outerHTML); // do what you want
});

myFrame.src = 'http://fiddle.jshell.net/';