JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.4/themes/ui-lightness/jquery-ui.css">
<h1>h1</h1>


<h3>h3</h3>


<h2>h2-1</h2>


<h2>h2-2</h2>


<h2>h2-3</h2>


<h2>h2-4</h2>

<script>
    /*!
     * Sizzle CSS Selector Engine
     *  Copyright 2011, The Dojo Foundation
     *  Released under the MIT, BSD, and GPL Licenses.
     *  More information: http://sizzlejs.com/
     */ (function() {

        var chunker = /((?:\((?:\([^()]+\)|[^()]+)+\)|\[(?:\[[^\[\]]*\]|['"][^'"]*['"]|[^\[\]'"]+)+\]|\\.|[^ >+~,(\[\\]+)+|[>+~])(\s*,\s*)?((?:.|\r|\n)*)/g,
            done = 0,
            toString = Object.prototype.toString,
            hasDuplicate = false,
            baseHasDuplicate = true,
            rBackslash = /\\/g,
            rNonWord = /\W/;

        // Here we check if the JavaScript engine is using some sort of
        // optimization where it does not always call our comparision
        // function. If that is the case, discard the hasDuplicate value.
        //   Thus far that includes Google Chrome.
        [0, 0].sort(function() {
            baseHasDuplicate = false;
            return 0;
        });

        var Sizzle = function(selector, context, results, seed) {
            results = results || [];
            context = context || document;

            var origContext = context;

            if (context.nodeType !== 1 && context.nodeType !== 9) {
                return [];
            }

            if (!selector || typeof selector !== "string") {
                return results;
            }

            var m, set, checkSet, extra, ret, cur, pop, i,
            prune = true,
                contextXML = Sizzle.isXML(context),
                parts = [],
                soFar = selector;

            // Reset the position of the chunker regexp (start from head)
            do {
                chunker.exec("");
                m = chunker.exec(soFar);

                if (m) {
                    soFar = m[3];

  ...

JavaScript

var headings = Sizzle('h2');

for (var i = 0; i < headings.length; i++) {
    document.write('<ul>');
    document.write('<li>' + headings[i].innerHTML + '</li>');
    document.write('</ul>');
}