JSFiddle - React, Tailwind, and code Playground

HTML

<div id="box"></div>
<div id="out"></div>

CSS

#box {width:50px; height:50px; position:absolute; left:0;top:0; background:#c00;}
#out {border:1px solid #ccc; margin-top:100px;}

JavaScript

$(function () {

	$('#box').animate({'left':'100px'}, {
		duration: 300,
		step: function () {
			$('#out').append($('<div />').text($('#box').is(':animated')));
		}
	});

});