Date Time Picker for Warranty Start, Warranty End, Invoice Date in Same Page

var today = new Date();
var yyyy = today.getFullYear();
$('.purchase_date').datetimepicker({
    viewMode: 'years',
    format: 'DD-MMM-YYYY',
    extraFormats: [ 'DD.MM.YY', 'DD.MM.YYYY' ],
    maxDate: today,
    minDate: '01/01/' + (yyyy - 60)
});

$('.datepicker').datetimepicker({
    viewMode: 'years',
    format: 'DD-MMM-YYYY',
    extraFormats: [ 'DD.MM.YY', 'DD.MM.YYYY' ]
});


$('#warrantyStart').datetimepicker();
$('#warrantyEnd').datetimepicker({
    useCurrent: false //Important! See issue #1075
});
$("#warrantyStart").on("dp.change", function (e) {
    $('#warrantyEnd').data("DateTimePicker").minDate(e.date);
});
$("#warrantyEnd").on("dp.change", function (e) {
    $('#warrantyStart').data("DateTimePicker").maxDate(e.date);
});