JSFiddle - React, Tailwind, and code Playground

HTML

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

JavaScript

var dateString = 'Fri 21 Feb 2014, 09:40 AM';
var date = new Date(dateString);
var yr = date.getFullYear();
var mo = date.getMonth() + 1;
var day = date.getDate();

var hours = date.getHours();
var hr = hours < 10 ? '0' + hours : hours;

var minutes = date.getMinutes();
var min = (minutes < 10) ? '0' + minutes : minutes;

var seconds = date.getSeconds();
var sec = (seconds < 10) ? '0' + seconds : seconds;

var newDateString = yr + '-' + mo  + '-' + day;
var newTimeString = hr + ':' + min + ':' + sec;

var excelDateString = newDateString + ' ' + newTimeString;

document.getElementById('result').innerHTML = excelDateString;