Multiply two columns in GridView using jQuery in ASP.Net

I am trying to multiply two columns in GridView, but not getting done.

<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript">
    $(function () {
        $("[id*=txtrate]").val("0");
    });
    $("body").on("change keyup", "[id*=txtrate]", function () {
        //Check whether Quantity value is valid Float number.
        var rate = parseFloat($.trim($(this).val()));
        if (isNaN(rate)) {
            rate = 0;
        }
 
        //Update the Quantity TextBox.
        $(this).val(rate);
 
        //Calculate and update Row Total.
        var row = $(this).closest("tr");
        $("[id*=lblTotal]", row).html(parseFloat($(".grn_qty", row).html()) * parseFloat($(this).val()));
 
        //Calculate and update Grand Total.
        var grandTotal = 0;
        $("[id*=lblTotal]").each(function () {
            grandTotal = grandTotal + parseFloat($(this).html());
        });
        $("[id*=lblGrandTotal]").html(grandTotal.toString());
    });
</script>
    

Gridview

<asp:GridView ID="gvSelected" runat="server"
AutoGenerateColumns = "false" Font-Names = "Arial"
Font-Size = "11pt" AlternatingRowStyle-BackColor = "#C2D69B"
HeaderStyle-BackColor = "green" EmptyDataText = "No Records Selected" OnRowDataBound="gvSelected_RowDataBound"  >
    <Columns>
        <asp:BoundField ItemStyle-Width="150px" DataField="GRN_DID" HeaderText="ID" />
        <asp:BoundField ItemStyle-Width="150px" DataField="GRN_ID" HeaderText="GRN_ID" />
        <asp:BoundField ItemStyle-Width="150px" DataField="It_Name" HeaderText="Name" />
        <asp:BoundField ItemStyle-Width="150px" DataField="grn_qty" HeaderText="QTY" />
        <asp:TemplateField HeaderText="Rate" >
            <ItemTemplate>
                <asp:TextBox ID="txtrate" runat="server" Width="50px"  Text='<%#Bind("txtrate")%>'></asp:TextBox>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField HeaderText="Total" >
            <ItemTemplate>
                <asp:Label ID="lbtotal" runat="server" Width="50px" Text='<%#Bind("lbtotal")%>'></asp:Label>
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>