JSFiddle - React, Tailwind, and code Playground

HTML

<div class="slide">
  
</div>

CSS

.slide{
  background-color:red;
  width:50px;
  height:50px;
  left:10%;
  top:50%;
  position:absolute;
}

JavaScript

$('.slide').animate({
	left:'100%'
},2000);
setTimeout(function(){
	$('.slide').stop();
	alert(getLeft($('.slide')));
},1000);
function getLeft(slide){
    return (100 / $(window).width()) * parseInt(slide.css('left').split('px')[0]) + '%';
}