I worked with your code as follows.
<body>
<form id="form1" runat="server">
<div>
<div id="divStatus" runat="server">
<asp:TextBox runat="server" ID="txtATQuantityATC" CssClass="TxtATQuantityATC"></asp:TextBox>
<asp:Label ID="lblATUPriceATC" runat="server" CssClass="LblATUPriceATC">10</asp:Label >
<asp:Label ID="lblATTotalAmntATC" runat="server" CssClass="LblATTotalAmntATC">Total Amount:</asp:Label >
</div>
</div>
</form>
</body>
and its javascript code
<script type="text/javascript">
$(document).ready(function () {
$(".TxtATQuantityATC").blur(function () {
var price = $(".LblATUPriceATC").text();
//alert($(".LblATTotalAmntATC").text());
var totalAmount = $(".LblATTotalAmntATC");
var total = parseInt(this.value) * parseFloat(price);
totalAmount.text(total);
});
});
</script>
I found it is working without postback. Just make sure that your html/asp.net control is same. Let me know if any difference you found. In javascript debug you can use firfox's firebug tool. You can also use console.log/window.alert method for know the run time value.