JSFiddle - React, Tailwind, and code Playground

HTML

<div id='parent'></div>

JavaScript

var button = $("<input type='button' value='click me' />");

var frameBody = $('<iframe id="someId"/>')
	.appendTo('#parent')
	.contents().find('body');

var script   = document.createElement("script");
script.type  = "text/javascript";
script.text  = "function alertUser(){alert('hello');}"
frameBody.append(script);

button.click(alertUser);
frameBody.append(button);