JSFiddle - React, Tailwind, and code Playground

HTML

<form id="list_form"><fieldset><select id="sel"><option id="list_opt">1</option><option>2</option><option>3</option></select></fieldset></form>

<div id="test"></div>

JavaScript

$(function(){
    var msg = "jQuery.support.optSelected: " + $.support.optSelected + "<br />";
    
    var select = document.createElement('select'),
        opt = select.appendChild( document.createElement('option') );
    
    msg += "Pseudo &lt;option&gt; from var opt: " + opt.selected + "<br />";
    
    msg += "Pseudo &lt;option&gt; from childNodes : " + select.childNodes[0].selected + "<br />";
    
    msg += "Real &lt;option&gt; from id : " + document.getElementById('list_opt').selected + "<br />";

    msg += "Qty &lt;option&gt;s: " + document.getElementById('sel').childNodes.length + "<br />";

    
    $('#test').html(msg);
});