My97DatePicker日期如何只显示年?或如何只显示年月？

<tr>
                            <td align="left">
                                <div class="xz">
                                            <table width="100%" cellpadding="0" align="left"  cellspacing="0" border="0">
                                            <tr>
                                                <td>&nbsp;&nbsp;统计时间：

                                                    <asp:DropDownList ID="DropDownListDateTimeFiled" runat="server" Width="100px" Height="20px">
                                                        <asp:ListItem Value="0">签署时间</asp:ListItem>
                                                        <asp:ListItem Value="1">开始时间</asp:ListItem>
                                                        <asp:ListItem Value="2">结束时间</asp:ListItem>
                                                        <asp:ListItem Value="3">到款时间</asp:ListItem>
                                                    </asp:DropDownList>
                                                    <asp:TextBox ID="txtStartDate" runat="server" Width="70px" Height="20px" onclick="WdatePicker({dateFmt:'yyyy-MM'})"></asp:TextBox>
                                                    至<asp:TextBox ID="txtEndDate" runat="server" Width="70px" Height="20px" onclick="WdatePicker({dateFmt:'yyyy-MM'})"></asp:TextBox>
                                                </td>
                                                <td>
                                                    &nbsp;大区名称：<asp:DropDownList ID="DropDownListDepartment" runat="server" Width="150px" Height="20px" DataSourceID="ObjectDataSource6" DataTextField="DepartmentName" DataValueField="DepartmentID"></asp:DropDownList>
                                                    <asp:ObjectDataSource ID="ObjectDataSource6" runat="server" SelectMethod="DepartmentList" TypeName="Contract.BLL.CustomerTrialControler"></asp:ObjectDataSource>

                                                </td>
                                                <td>
                                                    
                                                    &nbsp;业务员：<asp:DropDownList ID="DropDownListSaler" runat="server" Width="100px" Height="20px" ></asp:DropDownList>

                                                </td>
                                                <td>&nbsp;&nbsp;<asp:ImageButton ID="ImageButton1" runat="server" ImageUrl="~/Images/ReportButton.gif"
                                                     OnClick="ImageButton1_Click"/></td>
                                            </tr>
                                            </table>
                                </div>
                            </td>
                        </tr>

注：

只显示年：onclick="WdatePicker({ dateFmt: 'yyyy', minDate: '1900', maxDate: '2099' })"

只显示年月 onclick="WdatePicker({ dateFmt: 'yyyy-MM', minDate: '1900', maxDate: '2099' })"