How do I get the difference between two Dates in JavaScript?

Question

I\'m creating an application which lets you define events with a time frame. I want to automatically fill in the end date when the user selects or changes the start date.

Answer 1

Below code will return the days left from today to futures date.

Dependencies: jQuery and MomentJs.

var getDaysLeft = function (date) {
  var today = new Date();
  var daysLeftInMilliSec = Math.abs(new Date(moment(today).format('YYYY-MM-DD')) - new Date(date));
  var daysLeft = daysLeftInMilliSec / (1000 * 60 * 60 * 24);   
  return daysLeft;
};

getDaysLeft('YYYY-MM-DD');