Monthpicker instantiation - Last of the month

// This monthpicker requires my monthpicker.js and monthpicker.css available here: https://pastebin.com/u/Ultroman
// If you want to see the instructions, go to this StackOverflow post: https://stackoverflow.com/a/26011321/1289974

    // The value retrieved from this monthpicker, is always the LAST day of the selected month.
    // Starts at the current month. Ranges from 100 years in the past to 10 years into the future.
        $('#end').monthpicker({
            dateFormat: 'MM yy',
            changeMonth: true,
            changeYear: true,
            showMonthAfterYear: true,
            showAnim: "drop",
            constrainInput: true,
            yearRange: "-100Y:+10Y",
            minDate: new Date(new Date().getFullYear() - 100, new Date().getMonth() + 1, 0),
            maxDate: new Date((new Date().getFullYear() + 10), new Date().getMonth() + 1, 0),
            defaultDate: new Date(new Date().getFullYear(), new Date().getMonth() + 1, 0),

            onClose: function (dateText, inst) {
                var date = new Date(inst.selectedYear, inst.selectedMonth + 1, 0);
                $(this).monthpicker('option', 'defaultDate', date);
                $(this).monthpicker('setDate', date);
            },

            beforeShow: function (input, inst) {
                if ($(this).monthpicker("getDate") !== null) {
                    // Making sure that the date set is the last of the month.
                    var date = new Date(inst.selectedYear, inst.selectedMonth + 1, 0);
                    if($(this).monthpicker("getDate").getDate() !== date){
                        $(this).monthpicker('option', 'defaultDate', date);
                        $(this).monthpicker('setDate', date);
                    }
                } else {
                    // If the date is null, we reset it to the defaultDate. Make sure that the defaultDate is always set to the last of the month!
                    $(this).monthpicker('setDate', $(this).monthpicker('option', 'defaultDate'));
                }
            },

            onChangeMonthYear: function (year, month, inst) {
                $(this).val($.monthpicker.formatDate($(this).monthpicker('option', 'dateFormat'), new Date(year, month, 0)));
            }
        })
        //.after( // this makes a link labeled "clear" appear to the right of the input-field, which clears the text in it
        //    $("<a href='javascript: void(0);'>clear</a>").click(function() {
        //        $(this).prev().val('');
        //    })
        //)
        ;