then do following,
$("[id*=TextBox3]").live("keyup", function () {
if (!jQuery.trim($(this).val()) == '') {
if (!isNaN(parseFloat($(this).val()))) {
var row = $(this).closest("tr");
var total = parseFloat($("[id*=price]", row).val()) * parseFloat($(this).val());
var total = !isNaN(total) ? total : 0;
$("[id*=lblTotal]", row).html(total); }
} else { $(this).val(''); } var grandTotal = 0;
$("[id*=lblTotal]").each(function () {
grandTotal = grandTotal + parseFloat($(this).html()); });
if (isNaN(grandTotal)) { grandTotal = 0; }
$("[id*=lblGrandTotal]").html(grandTotal.toString()); });
$("[id*=price]").live("keyup", function () {
if (!jQuery.trim($(this).val()) == '') {
if (!isNaN(parseFloat($(this).val()))) {
var row = $(this).closest("tr");
var total = parseFloat($("[id*=TextBox3]", row).val()) * parseFloat($(this).val());
var total = !isNaN(total) ? total : 0;
$("[id*=lblTotal]", row).html(total); }
} else { $(this).val(''); } var grandTotal = 0;
$("[id*=lblTotal]").each(function () {
grandTotal = grandTotal + parseFloat($(this).html()); });
if (isNaN(grandTotal)) { grandTotal = 0; }
$("[id*=lblGrandTotal]").html(grandTotal.toString()); });