Study plugin

if (this.showDropdowns) {
                var currentMonth = calendar[1][1].month();
                var currentYear = calendar[1][1].year();
                var maxYear = (maxDate && maxDate.year()) || (currentYear + 5);
                var minYear = (minDate && minDate.year()) || (currentYear - 50);
                var inMinYear = currentYear == minYear;
                var inMaxYear = currentYear == maxYear;

                var monthHtml = '<select class="monthselect form-control">';
                for (var m = 0; m < 12; m++) {
                    if ((!inMinYear || m >= minDate.month()) && (!inMaxYear || m <= maxDate.month())) {
                        monthHtml += "<option value='" + m + "'" +
                            (m === currentMonth ? " selected='selected'" : "") +
                            ">" + this.locale.monthNames[m] + "</option>";
                    } else {
                        monthHtml += "<option value='" + m + "'" +
                            (m === currentMonth ? " selected='selected'" : "") +
                            " disabled='disabled'>" + this.locale.monthNames[m] + "</option>";
                    }
                }