Date Difference Function in java script

/*---------------------Find DateDifference in java script-------------------*/

function Datediffrence(datefrom, dateto) {

    var startDate = Date.parse(datefrom);

    var endDate = Date.parse(dateto);

    var timeDiff = endDate - startDate;

    daysDiff = Math.floor(timeDiff / (1000 * 60 * 60 * 24));

    return daysDiff;

}

Example : How to find date diffenece not greater than 30 days

      //No.of Days Difference

        function FindDateDifference(sender, args) {

            var daysDiff = Datediffrence(document.getElementById('<%=txtDateFrom.ClientID %>').value, document.getElementById('<%=txtDateTo.ClientID %>').value)

            if (daysDiff > 30) {

                args.IsValid = false;

            }

            else {

                args.IsValid = true;

            }

        }