My97DatePicker 只显示月份

<script src="../javascript/My97DatePicker/WdatePicker.js" type="text/javascript"></script>  

<script>
    function selectMonth() {
        WdatePicker({ dateFmt: 'yyyy-MM', isShowToday: false, isShowClear: false });
    }
</script>  

<input id="starttime" type="text" style="width: 70px;" runat="server" onfocus="selectMonth()" />