JSFiddle - React, Tailwind, and code Playground

HTML

<!doctype html>
<title>iframe</title>
<body><script>
var
iframe = document.body.appendChild(document.createElement('iframe')),
iframe_document = iframe.contentWindow.document;

iframe.style.width = '100%';

iframe.contentWindow.addEventListener('resize', function (event) {
	console.log(event.type, Date.now());
})

iframe.onload = function () {
	iframe.contentWindow.document.body.style.cssText = 'background-color: red';

	iframe.contentWindow.document.body.innerHTML = 'Hello, World!';
};
</script></body>