How to set calendar on popup text box

Question

Work on Asp.net VS 08 C#. Want to use jquery calendar on popup text box .If i use my syntax out side the popupn div than it's work .Why it's not work on popup div.How to use it?

Popup div

<div id="divEditCustomerDlgContainer">
        <div id="divEditCustomer" style="display: none">
            <asp:UpdatePanel ID="upnlEditCustomer" runat="server">
                <ContentTemplate>
                    <asp:PlaceHolder ID="phrEditCustomer" runat="server">
                        <table cellpadding="3" cellspacing="1">
                            <tr>
                                <td>
                                    *First Name:
                                </td>
                                <td>
                                    <asp:TextBox ID="txtFirstName" Columns="40" MaxLength="50" runat="server" />
                                    <asp:RequiredFieldValidator ID="vtxtFirstName" runat="server" EnableClientScript="false"
                                        CssClass="ui-state-error-text" Display="Dynamic" ErrorMessage="Required." ControlToValidate="txtFirstName" />
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    *Last Name:
                                </td>
                                <td>
                                    <asp:TextBox ID="txtLastName" Columns="40" MaxLength="50" runat="server" />
                                    <asp:RequiredFieldValidator ID="vtxtLastName" runat="server" EnableClientScript="false"
                                        CssClass="ui-state-error-text" Display="Dynamic" ErrorMessage="Required." ControlToValidate="txtLastName" />
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    *Email:
                                </td>
                                <td>
                                    <asp:TextBox ID="txtEmail" Columns="40" MaxLength="50" runat="server" />
                                    <asp:RequiredFieldValidator ID="vtxtEmail" runat="server" EnableClientScript="false"
                                        CssClass="ui-state-error-text" Display="Dynamic" ErrorMessage="Required." ControlToValidate="txtEmail" />
                                    <asp:RegularExpressionValidator ID="vtxtEmail2" runat="server" EnableClientScript="false"
                                        CssClass="ui-state-error-text" ControlToValidate="txtEmail" ValidationExpression=".*@.*\..*"
                                        ErrorMessage="Not a valid email." Display="Dynamic" />
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    Phone:
                                </td>
                                <td>
                                    <asp:TextBox ID="txtPhone" Columns="20" MaxLength="20" runat="server" />
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    Date of Birth:
                                </td>
                                <td>
                                    <%--<asp:TextBox ID="txtDateOfBirth" Columns="10" MaxLength="20" runat="server" />
                                    <asp:CompareValidator ID="vtxtDateOfBirth" runat="server" EnableClientScript="false"
                                        CssClass="ui-state-error-text" ControlToValidate="txtDateOfBirth" ErrorMessage="Not a valid date."
                                        Operator="DataTypeCheck" Type="Date" />--%>

                                       <asp:TextBox ID="dtpCalendar" runat="server" Text='<%# Bind("BirthDate") %>' onkeydown = "return (event.keyCode==9);"></asp:TextBox>

                                </td>
                            </tr>
                            <tr>
                                <td colspan="2" align="right">
                                    <asp:Button ID="btnSave" OnClick="btnSave_Click" Text="Save" runat="server" />
                                    <asp:Button ID="btnCancel" OnClick="btnCancel_Click" OnClientClick="closeDialog()"
                                        CausesValidation="false" Text="Cancel" runat="server" />
                                    <asp:Button ID="Button1" Text="Hello" runat="server" CausesValidation="false" OnClick="Button1_Click" />
                                </td>
                            </tr>
                        </table>
                    </asp:PlaceHolder>
                </ContentTemplate>
            </asp:UpdatePanel>
        </div>
    </div>

Calendar TextBox

 <asp:TextBox ID="dtpCalendar" runat="server" Text='<%# Bind("BirthDate") %>' onkeydown = "return (event.keyCode==9);"></asp:TextBox>

calendar Jquery syntax

 <script type="text/javascript">
          $(document).ready((function() {
              //        $("#dtpCalendar").datepicker();
              $("#<%=dtpCalendar.ClientID%>").datepicker({ dateFormat: 'dd-M-yy' });
          }));
     </script>