TextBox does not get it's value from code behind after postback

Question

please consider this code:

<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
    <ContentTemplate>
        <table border="1" cellpadding="8" cellspacing="0" width="700px" style="background-color: Aqua">
            <tr>
                <td style="direction: rtl">
                    &nbsp;
                    <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
                </td>
                <td style="direction: ltr">
                    F1
                </td>
            </tr>
            <tr>
                <td style="direction: rtl">
                    <asp:DropDownList ID="Drp_1" runat="server" ClientIDMode="Static">
                        <asp:ListItem Value="1">Head of household</asp:ListItem>
                        <asp:ListItem Value="2">Spouse</asp:ListItem>
                        <asp:ListItem Value="3">Child</asp:ListItem>
                    </asp:DropDownList>
                </td>
                <td>
                    F2
                </td>
            </tr>
            <tr>
                <td style="direction: rtl">
                    <asp:RadioButtonList ID="Rad_7" runat="server" ClientIDMode="Static">
                        <asp:ListItem Text="1" Value="1"></asp:ListItem>
                        <asp:ListItem Text="2" Value="2"></asp:ListItem>
                        <asp:ListItem Text="3" Value="3"></asp:ListItem>
                        <asp:ListItem Text="4" Value="4"></asp:ListItem>
                    </asp:RadioButtonList>
                </td>
                <td>
                    F3
                </td>
            </tr>
            <tr>
                <td>
                    <asp:Button ID="BindAgain" runat="server" Height="44px" Text="Submit" ClientIDMode="Static"
                        Width="207px" OnClick="BindAgain_Click" />
                </td>
                <td>
                    <asp:Button ID="btn" runat="server" Height="44px" Text="Submit" ClientIDMode="Static"
                        Width="207px" OnClick="btn_Click" />
                </td>
            </tr>
        </table>
    </ContentTemplate>
</asp:UpdatePanel>
<asp:TextBox ID="isPostback" ClientIDMode="Static" runat="server"></asp:TextBox>
<h1 style="color: Green; font-size: large; font-weight: bold; display: none;" id="nima">
    Progress ...
</h1>

and this is code bihind:

    protected void btn_Click(object sender, EventArgs e)
{
    System.Threading.Thread.Sleep(4000);
    TextBox1.Text = "nima";
}
protected void BindAgain_Click(object sender, EventArgs e)
{
    Drp_1.SelectedIndex = 1;
    Rad_7.SelectedIndex = 3;
    isPostback.Text = "1";
}

when I want to check value of isPostback after postback using jQuery I get "" .this is my javascript code:

function pageLoad() {
        $('#nima').hide();
        $(document).ready(function () {
            //alert("NIMA");
            $("#Drp_1").on("change", function () {
                if ($(this).val() == 2) {
                    if ($('#Rad_7 input:checked').val() != null && $('#Rad_7 input:checked').val() > 1 && $('#Rad_7 input:checked').val() != 2) {
                        if ($('#isPostback').val() == "0") {//<<<<<<<<
                            alert('Wrong option');
                        }
                    }
                }
                else {
                    $('#Rad_7 input').removeAttr("checked");
                }
            }).change();


            $("#Rad_7 input").on("change", function () {
                if ($(this).val() == 2) {
                    if ($('#Drp_1').val() != null && $('#Drp_1').val() > 1 && $('#Drp_1').val() != 2) {
                        if ($('#isPostback').val() == "0") {//<<<<<<<<
                            alert('Wrong option');
                        }
                    }
                }

                if ($("#Drp_1").val() != null && $("#Drp_1").val() == 2) {
                    if ($('#Rad_7 input:checked').val() != null && $('#Rad_7 input:checked').val() != 'undefiend' && $('#Rad_7 input:checked').val() != 2) {
                        if ($('#isPostback').val() == "0") {//<<<<<<<<
                            alert('Wrong option');
                        }
                    }
                }
            }).change();

        });
    }

    var prm = Sys.WebForms.PageRequestManager.getInstance();
    prm.add_initializeRequest(InitializeRequest);
    prm.add_endRequest(EndRequest);

    function InitializeRequest(sender, args) {
        $('#nima').css('display', 'block');
    }
    function EndRequest(sender, args) {
        $('#nima').css('display', 'none');
    }

where is my mistake?

thanks

Answer 1

Your textbox is outside of the UpdatePanel. It is not receiving the update when the postback is triggered from within the panel.