modal popup not display

protected void popup_Click(object sender, EventArgs e)
{
    // Show ModalPopUpExtender.
    ModalPopupExtender1.Show();
    Panel1.Visible = true;

}

<asp:ScriptManager ID="ScriptManager1" runat="server">

<asp:Button ID="Button1" runat="server" Text=""/>
<ajaxToolKit:ModalPopupExtender ID="ModalPopupExtender1"  runat="server" CancelControlID="btncancel"
TargetControlID="Button1" PopupControlID="Panel1" PopupDragHandleControlID="PopupHeader"
Drag="true" BackgroundCssClass="ModalPopupBG">

<asp:Panel ID="Panel1" Style="display: none" runat="server">
<div class="HellowWorldPopup">
<div class="PopupBody">
<div class="PopupHeader" id="PopupHeader" style="background-color: #009000; margin-removed 0px;<br mode=" hold=" />                    height: 20px; color: white">
    Contact to Dr  <asp:Label
    ID="lblDocname" runat="server"></div>
</div>
<div class="Controls">
<table style="height: 280px; width: 450px; margin-removed 25px;">
<tr>
    <td>
        <asp:Label ID="lblInfo" runat="server">
    </td>
</tr>
<tr>
    <td style="padding-removed 20px; vertical-align: top;">
        Name:
    </td>
    <td style="vertical-align: top;">
        <asp:TextBox ID="txtName" runat="server" Height="23px">
    </td>
</tr>
<tr>
    <td style="padding-removed 20px; vertical-align: top;">
        Mobile No.:
    </td>
    <td style="vertical-align: top;">
        <asp:TextBox ID="txtMobile" runat="server" Height="23px">
    </td>
</tr>
<tr>
    <td style="padding-removed 20px; vertical-align: top;">
        Email Address:
    </td>
    <td style="vertical-align: top;">
        <asp:TextBox ID="txtAddress" runat="server" Height="23px">
    </td>
</tr>
<tr>
    <td style="padding-removed 20px; vertical-align: top;">
        Query:
    </td>
    <td style="vertical-align: top;">
        <asp:TextBox ID="txtQuery" runat="server" TextMode="MultiLine">
    </td>
</tr>
<tr>
    <td style="padding-removed 90px; vertical-align: top;">
        <asp:Button ID="btnSend" runat="server" Text="Send Now" OnClick="btnSend_Click" Style="background-color: #195905;
            color: White; vertical-align: top; height: 23px; width: 70px;" />
    </td>
    <td style="margin-removed 25px;">
        <asp:Button ID="btncancel" runat="server" Text="Cancel" Style="background-color: #195905;
            vertical-align: top; color: White; height: 23px; width: 70px;" />
    </td>
</tr>
</table>
</div></div>