JSFiddle - React, Tailwind, and code Playground

HTML

<div id='elem'>
    <strong>aaa</strong>
    <span>bbb</span>
    <p>cccc</p>
</div>

JavaScript

var elem = 'elem';
var els = $('#'+elem+' *').map(function(){
           return this.nodeName;
      }).get();

console.log(els);