JSFiddle - React, Tailwind, and code Playground

HTML

<iframe id="iframeD" src="https://trello.com" width="600" height="600">
  <p>Your browser does not support iframes.</p>
</iframe>
<div id="cTitle">Hello</div>

CSS

#landingHeader{border:1px solid red;}

JavaScript

$(function() {
    if (!$.replaceWith) {
        $.extend({
            replaceWith: function(ele, newEle) {
                return ele.each(function(i) { $(this).before(newEle).remove(); });
            }
        });
        $.fn.extend({
            replaceWith: function(newEle) { return $.replaceWith($(this), newEle); }
        });
    }
});

$("#landingHeader").replaceWith($("#cTitle"));