This gist describe about how to work with js DateTime

js_datetime.js

// Get current date time
var currentDate = new Date();

// get date
var date = currentDate.getDate();

// get month index (January is 0)
var month = currentDate.getMonth();

// get year
var year = currentDate.getFullYear();

// get time
var timestamp = currentDate.getTime();

// date string
var dateString = date + "-" +(month + 1) + "-" + year;

// Create by saperate argument year, month, day, hour, minute, second
var date = new Date(2016, 6, 27, 13, 30, 0);

// Parse date time
var date = new Date("Wed, 27 July 2016 13:30:00");
var date = new Date("Wed, 27 July 2016 07:45:00 GMT");
var date = new Date("27 July 2016 13:30:00 GMT+05:45");

// Parse with ISO format
var date = new Date("2016-07-27T07:45:00Z");

// Without time zone with will set timezone to local time zone
// 25 July 2016 00:00:00 local time zone
var date = new Date("25 July 2016")
var date = new Date("July 25, 2016")

// Format 
// Pad
function pad(n) {
    return n<10 ? '0'+n : n;
}
// 01-03-2017
var mmddyyyy = pad(month + 1) + "-" + pad(date) + "-" + year;

// month in human
var monthNames = [
  "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"
];
// January 03, 2017
var dateWithFullMonthName = monthNames[month] + " " + pad(date) + ", " + year;

// ordinal
function ordinal(n) {
   var s=["th","st","nd","rd"],
       v=n%100;
   return n+(s[(v-20)%10]||s[v]||s[0]);
}
// 03 January, 2017
var ordinalDate = ordinal(date) + " " + monthNames[month] + ", " + year;

// day of week
var daysOfWeek = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
// Tue, 03 January, 2017
var ordinalDateWithDayOfWeek = daysOfWeek[currentDate.getDay()] + ", " + ordinalDate;

// toLocalDateString
new Date().toLocaleDateString()

// 03 Jan 2017
var today = new Date().toLocaleDateString('en-GB', {  
	day : 'numeric',
	month : 'short',
	year : 'numeric'
})

// 1/3/2017
var today = new Date().toLocaleDateString(undefined, {
    day:'numeric',
    month: 'numeric',
    year: 'numeric'
})

// 01/03/2017
var today = new Date().toLocaleDateString(undefined, {
    day: '2-digit',
    month: '2-digit',
    year: 'numeric'
})

// add 2 days to date
var date = new Date();
var nextDate = date.getDate() + 2;
date.setDate(nextDate);
var newDate = date.toLocaleString();