JSFiddle - React, Tailwind, and code Playground

JavaScript

var startDate = "7/11/2012 20:30:00";
var endDate = "20/11/2012 19:15:00";

var parts = startDate.split('/');
startDate = parts[1] + '/' + parts[0] + '/' + parts[2];

var parts = endDate.split('/');
endDate = parts[1] + '/' + parts[0] + '/' + parts[2];

var date1 = new Date(startDate);
var date2 = new Date(endDate);



var diff = date2.getTime() - date1.getTime();

var days = Math.floor(diff / (1000 * 60 * 60 * 24));
diff -=  days * (1000 * 60 * 60 * 24);

var hours = Math.floor(diff / (1000 * 60 * 60));
diff -= hours * (1000 * 60 * 60);

var mins = Math.floor(diff / (1000 * 60));
diff -= mins * (1000 * 60);

var seconds = Math.floor(diff / (1000));
diff -= seconds * (1000);

alert(days + " days : " + hours + " hours : " + mins + " minutes : " + seconds + " seconds");