JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="accordion">
    <li><h3>title</h3></li>
    <li><h3>title</h3></li>
    <li><h3>title</h3></li>
</ul>

JavaScript

var h3 = $("h3")[0];
    
var test1 = $(h3).closest(">li", $("#accordion")[0]).length;
var test2 = $(h3).closest(">li").length;
alert(test1);
alert(test2);