Keep (retain) TextBox text after Button Click using jQuery in ASP.Net

Use below code.

<form id="form1" runat="server">
    <asp:ScriptManager runat="server" />
    <div id="DDlM2">
        <asp:UpdatePanel ID="UpTran" runat="server">
            <ContentTemplate>
                <asp:DropDownList ID="Ddlmetraj" runat="server" CssClass="ddmetM" AutoPostBack="true">
                    <asp:ListItem Text="Select" Value=""></asp:ListItem>
                    <asp:ListItem Text="test 1" Value="1"></asp:ListItem>
                    <asp:ListItem Text="test 2" Value="2"></asp:ListItem>
                    <asp:ListItem Text="test 3" Value="3"></asp:ListItem>
                </asp:DropDownList>
            </ContentTemplate>
        </asp:UpdatePanel>
    </div>
    <asp:UpdatePanel ID="UpdatePanel5" runat="server">
        <ContentTemplate>
            <div id="Div1" runat="server" visible="true">
                <asp:TextBox ID="Txtvadie1" runat="server" CssClass="txtvadi2" ForeColor="#443f13" Text="تا"
                    onpaste="return false;" placeholder="number1"></asp:TextBox>
                <asp:TextBox ID="Txtvadie2" runat="server" CssClass="txtvadi2" ForeColor="#443f13" Text="تا"
                    onpaste="return false;" placeholder="number2"></asp:TextBox>
            </div>
        </ContentTemplate>
    </asp:UpdatePanel>
    <div id="Dview1">
        <asp:ImageButton ID="ImageButton2" runat="server" CssClass="imgviewM1" ImageUrl="~/Image/main/createGalary.png" AlternateText="Create" OnClick="ImageButton1_Click"></asp:ImageButton>
    </div>
</form>
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery-price-format/2.1/jquery.priceformat.min.js"></script>
<script type="text/javascript">
    $(function () {
        ApplyThousandSeparator();
    });
    function ApplyThousandSeparator() {
        $('#Txtvadie2, #Txtvadie1').priceFormat({
            prefix: '',
            thousandsSeparator: ',',
            centsSeparator: ',',
            limit: 12,
            centsLimit: 0
        });
        if ($('#Txtvadie1').val() == "0") {
            $('#Txtvadie1').val('number1');
        }
        if ($('#Txtvadie2').val() == "0") {
            $('#Txtvadie2').val('number2');
        }
        if ($('#Txtvadie1').val() != 'number1') {
            $('#Txtvadie1').val($('#Txtvadie1').val());
        }
        if ($('#Txtvadie2').val() != 'number2') {
            $('#Txtvadie2').val($('#Txtvadie2').val());
        }
    }
    var prm = Sys.WebForms.PageRequestManager.getInstance();
    if (prm != null) {
        prm.add_endRequest(function (sender, e) {
            if (sender._postBackSettings.panelsToUpdate != null) {
                ApplyThousandSeparator();
                $('#Txtvadie1').val($('#Txtvadie1').val());
                $('#Txtvadie2').val($('#Txtvadie2').val());
            }
        });
    };
</script>