how to pass hidden field value to javascript function

Hi friends,
I am using C#,asp.net, .net framework2.
I am using the following javascript

<script type="text/javascript">

function funcsum(id)

{


var table = document.getElementById("grdView");




var sum = 0;

var mess=0;

var mess1=0;

mess=table.rows[id].cells[7].getElementsByTagName("input")[0].value;

mess1=table.rows[id].cells[8].getElementsByTagName("input")[0].value;



sum=parseFloat(mess.replace(",","."))+parseFloat(mess1.replace(",","."));







var grid = document.getElementById("<%= grdView.ClientID %>");

//sum = grid.rows[1].cells[7].childNodes[0].value;

grid.rows[id].cells[9].childNodes[0].value = sum;





}



</script>

i am using a hidden field

<asp:HiddenField ID="HFRowNo" runat="server" Value='<%# Eval("rowNo") %>' />



I have to pass the value of rowno to javascript function in the textbox of  template column.
How to do this?


<asp:TemplateField HeaderText="P &amp; L As Per Book">

<ItemStyle Width="80px" BackColor="White"/>

<ItemTemplate>

<asp:TextBox Width="80px" ID="txtPL" runat="server" text='<%# Eval("PL") %>' BorderStyle="None" BorderColor="white" OnChange="funcsum(<%# Eval("rowNo") %>)" AutoPostBack="false" >

</asp:TextBox>

</ItemTemplate>

<FooterTemplate>

<asp:Label ID="lblFPL" runat="server" />

</FooterTemplate>


<ControlStyle Width="80px" />

</asp:TemplateField>