JSFiddle - React, Tailwind, and code Playground

HTML

<button id="show">show</button>
<div id="calendar" tabindex="0"></div>

CSS

#calendar{
    width:200px;
    height:200px;
    background-color:#00f;
    display:none;
}

JavaScript

$(document).ready(function(){
    $('#show').click(function(e){
        $('#calendar').show(200);
    });
    
    $('#calendar').focusout(function(e){
        $(this).hide(200);
    });
});