JSFiddle - React, Tailwind, and code Playground

HTML

fugahoge
<div>
    <button id="withShadow">with shadow</button>
</div>
<div>
    <button id="withContent">with content</button>
</div>
piyopiyo

JavaScript

var sr1 = new WebKitShadowRoot(withShadow);
sr1.innerHTML = "hoge<shadow></shadow>hopge";

var sr2 = new WebKitShadowRoot(withContent);
sr2.innerHTML = "figa<content></content>fuga";