JSFiddle - React, Tailwind, and code Playground

HTML

<div id="ej"></div>
<span id="result"></span>

CSS

#ej{
    border:1px solid red;
    width:200px;
    height:100px;
}

JavaScript

$(document).ready(function(){

$('#ej').mousedown(function(e){
	var rxd = e.pageX;
	var ryd = e.pageY;
	
	$(this).mouseup(function(f){
		var rxu = f.pageX;
		var ryu = f.pageY;
		$('#result').text(rxu-rxd);
	});
    return false;
});

});