JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="myUl">
    <li><a href="page.html">Page1</a>
        <ul>
            <li><a href="sub1.html">sub page 1</a></li>
            <li><a href="sub2.html">sub page 2</a></li>
        </ul>
    </li>
</ul>

CSS

#myUl li ul{display:none;}

JavaScript

$(function(){
    $('#myUl').children('li').click(function(){
        $(this).children('ul').toggle();
        return false;
    });
});