How to trigger update panel animation on textbox changed

if (SM1 !=null)
           {
           TextBox JNTB = (TextBox)e.Row.FindControl("JobNotesTB");
           if (JNTB != null)
           {
               SM1.RegisterAsyncPostBackControl(JNTB);
           }
           }

<asp:UpdatePanel ID="UP1" runat="server" >
      
        <ContentTemplate>
            
      <asp:Label ID="Bay1Label" runat="server"  Text="Bay 1" CssClass="BayLabelStyle"></asp:Label>
             <asp:Button ID="UP1but" runat="server" Text="Update" OnClick="btn_Click" />
                    <asp:GridView ID="GV1" runat="server" width="100%" CssClass="Grid" AlternatingRowStyle-BackColor="Azure" AutoGenerateColumns="False" OnRowEditing="GVRowEdit" OnRowDataBound="GVRowDataBound"  AllowSorting="True" OnRowUpdating="GVRowUpdate" OnRowCancelingEdit="GVRowCancellingEdit"  >
        <Columns>
       
<asp:TemplateField HeaderText="Jobs / Notes"  ItemStyle-HorizontalAlign="Center" HeaderStyle-CssClass="JobNotesCol">
                <EditItemTemplate>
                             <asp:TextBox  ID="JobNotesEditTB" runat="server" Text='<%# Bind("JobNotes") %>'  TextMode="MultiLine" Height="98%" Width="98%" class="expand" ></asp:TextBox>
                </EditItemTemplate>
                 <ItemTemplate>
                            <asp:TextBox ID="JobNotesTB"  runat="server" Text='<%# Bind("JobNotes") %>' OnTextChanged="TB_TextChanged" onchange="return: FadeGV();" TextMode="MultiLine"  style="height:98%; width:98%;" class="expand" AutoPostBack="True" CssClass="expand"></asp:TextBox> 
                </ItemTemplate>
            </asp:TemplateField> 
</ContentTemplate>
</asp:UpdatePanel>

<ajaxToolkit:UpdatePanelAnimationExtender ID="UPAE2"  runat="server" TargetControlID="UP1"  BehaviorID="animation" >
        <Animations>
            <OnUpdated>
                  <Parallel duration="0">
      <FadeIn  Duration="5.0" Fps="20" AnimationTarget="GV1" minimumOpacity="0.2" />
                      </Parallel>
            </OnUpdated> 
                <OnUpdating>
                      <Parallel duration="0">
      <FadeOut Duration="5.0" Fps="20" AnimationTarget="GV1" minimumOpacity="0.2" />
                          </Parallel>
            </OnUpdating> 
        </Animations>
    </ajaxToolkit:UpdatePanelAnimationExtender>