JSFiddle - React, Tailwind, and code Playground
HTML
<a id="cal"></a>
<div id="calendar_wrap"></div>
CSS
a#cal{width:50px;height:50px;background:red;float:left;}
#calendar_wrap{display:none; width:100px; height:100px; background:black;float:left;}
JavaScript
jQuery(function() {
$('a#cal').hover(
function() {
$('#calendar_wrap').fadeIn("slow");
}, function() {
$('#calendar_wrap').fadeOut("slow");
});
});