JSFiddle - React, Tailwind, and code Playground

HTML

<div class='button'>Click</div>
<div class='dropdown'>
    <ul>
        <li>aaaaaaaaaaa</li>
        <li>aaaaaaaaaaa</li>
        <li>aaaaaaaaaaa</li>
    </ul>
</div>

CSS

.button {
    background-color:#ccc;
    width:60px;
}
.dropdown {
    display:none;
    background-color:#ccc;
    width:300px;
}

JavaScript

$(".button").click(function(e){
    $(".dropdown").show();
     e.stopPropagation();
});

$(".dropdown").click(function(e){
    e.stopPropagation();
});

$(document).click(function(){
    $(".dropdown").hide();
});