<script>
        $(function () {
            $("#datepicker").datepicker({
                changeMonth: true,
                changeYear: true,
                dateFormat: 'yy-mm'
            });
            $("#datepickerdf").datepicker({
                changeMonth: true,
                changeYear: true
            });
        });
    </script>
<p>Date with dateFormat:yy-mm: <input type="text" id="datepicker"></p>
<p>Date with dateFormat:default: <input type="text" id="datepickerdf"></p>