Try this
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
<script type="text/javascript">
$(function () {
$("[id*=txtQuantity]").val("0");
});
$("[id*=txtQuantity]").live("change", function () {
if (isNaN(parseInt($(this).val()))) {
$(this).val('0');
} else {
$(this).val(parseInt($(this).val()).toString());
}
});
$("[id*=txtQuantity]").live("keyup", function () {
if (!jQuery.trim($(this).val()) == '') {
if (!isNaN(parseFloat($(this).val()))) {
var row = $(this).closest("tr");
$("[id*=lblTotal]", row).html(parseFloat($(".price", row).html()) * parseFloat($(this).val()));
}
} else {
$(this).val('');
}
var grandTotal = 0;
$("[id*=lblTotal]").each(function () {
grandTotal = grandTotal + parseFloat($(this).html());
});
$("[id*=lblGrandTotal]").html(grandTotal.toString());
$("[id*=hfGrandTotal]").val(grandTotal.toString())
});
</script>
</head>
<body>
<form id="form1" runat="server">
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
<Columns>
<asp:BoundField DataField="Item" HeaderText="Item" />
<asp:BoundField DataField="Price" HeaderText="Price" ItemStyle-CssClass="price" />
<asp:TemplateField HeaderText = "Quantity">
<ItemTemplate>
<asp:TextBox ID="txtQuantity" runat="server"></asp:TextBox>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText = "Total">
<ItemTemplate>
<asp:Label ID="lblTotal" runat="server" Text="0"></asp:Label>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
Grand Total:
<asp:Label ID="lblGrandTotal" runat="server" Text="0"></asp:Label>
<asp:HiddenField ID="hfGrandTotal" runat="server" />
<asp:Button runat="server" Text="Button" OnClick = "Button1_Click" />
</form>
</body>
</html>
protected void Button1_Click(object sender, EventArgs e)
{
double total = double.Parse(Request.Form[hfGrandTotal.UniqueID]);
}
