JSFiddle - React, Tailwind, and code Playground

HTML

<a>click</a>

<div class="drop user-menu">user menu asd</div>

CSS

.drop {
    display:none;
    background:blue;
}
a {
    background:black;
    color:white;
}

JavaScript

$(function () { 
    $('a').on('click', function () {
        $('.drop.user-menu').fadeIn();

    });
    $('.drop.user-menu').on('focusout', function () {
        $(this).fadeOut();
        alert('antani');
    });
});