JSFiddle - React, Tailwind, and code Playground

HTML

<div id="menu">
    <div id="main_menu">Main Menu</div>
    <div id="submenu" style="display: none">Some submenu contents here</div>
</div>

JavaScript

$('#menu').hover(function () {
    $('#submenu').stop(true, false).slideDown();
},

function () {
    $('#submenu').stop(true, false).slideUp();
});