JQuery Datepicker Date Difference

This article helps to calculate date difference between two jquery date picker input fields. Result will be number of days between the selected dates.

var start_date=$('#campaigns-campaignstartdate').datepicker({ dateFormat: "dd-mm-yyyy" ,beforeShowDay: NotBeforeToday}).val().split("-");
var end_date = $('#campaigns-campaignenddate').datepicker({ dateFormat: "dd-mm-yyyy" ,beforeShowDay: NotBeforeToday}).val().split("-");
var endDay = new Date(end_date[2], end_date[1] - 1, end_date[0]);var startDay = new Date(start_date[2], start_date[1] - 1, start_date[0]);
var diff= endDay-startDay;var days=diff/1000/60/60/24; 

function NotBeforeToday(date)
{ 
          var now = new Date();
          //this gets the current date and time
          if (date.getFullYear() == now.getFullYear() && date.getMonth() == now.getMonth() && date.getDate() > now.getDate())
                return [true]; 
          if (date.getFullYear() >= now.getFullYear() && date.getMonth() > now.getMonth())
                return [true]; 
          if (date.getFullYear() > now.getFullYear())
                return [true];
          return [false];
}