JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <div id="container">
        <div align="right">child</div>
        <div align="center">child</div>
        <embed src="" width="0" height="0" />
        <div align="center">child</div>
        <div style="width: 40px">child</div>
        <div style="font-size: 100px">child</div>
        <div width="60%">child</div>
        <embed src="" width="0" height="0"/>
        <div width="60%">child</div>
    </div>
</div>

JavaScript

var elm,
    clone,
    doc,
    next,
    fragment,
    live = document.getElementById("container");

if (live !== null) {
    fragment = document.createDocumentFragment();
    clone = live.cloneNode(true);
    next = clone.firstChild;
    while(next !== null) {
        if (next.nodeName !== "#text") {
            next.removeAttribute('style');
            next.removeAttribute('width');
            next.removeAttribute('align');
        
            if (next.tagName === 'EMBED') {
                doc = document.createElement('div');
                doc.setAttribute('class', 'video');
                doc.innerHTML = "EMBED detected, adding div...";
                fragment.appendChild(doc);
            }
        }
        next = next.nextSibling;
    }
    clone.appendChild(fragment);
    live.parentNode.replaceChild(clone, live);
}