JSFiddle - React, Tailwind, and code Playground

JavaScript

var tmp = '20/11/2013';
var myDateParts = tmp.split("/");                       
var oneDay = 24*60*60*1000;
var today = new Date();
var secondDate = new Date(myDateParts[2], myDateParts[1], myDateParts[0]);
var diffDays = Math.round(Math.abs((secondDate.getTime() - today.getTime()))/(oneDay));

console.log(secondDate);
console.log(diffDays+' days');