JSFiddle - React, Tailwind, and code Playground
HTML
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<link rel="import" href="sample.html">
</head>
<body>
<p>top</p>
<iframe src="sample.html" frameborder="0" id="myframe"></iframe>
<p>bottom</p>
<textarea cols="30" rows="10"></textarea>
</body>
</html>
JavaScript
var node = document.doctype;
console.log(node);
var all = document.getElementsByTagName("*");
for (var i=0, max=all.length; i < max; i++) {
console.log(all[i]);
}