How to assign and retrieve value from the GridView Cell using JavaScript?

I have Two Labels such as FixedTotal and TotalPercent, One GridView which has One Row such as

    ReferenceID       Percentage          Amount
   --------------    -------------       --------
   开发者_运维知识库     1                5                 1000

Here I want to change the "Percentage" Column value 5 with the TotalPercent label's text. and I want to display the "Amount" Column value 1000 in the FixedTotal label. I also want to check whether the Grid has row or not? How to do this? The Columns are BoundField Columns..

Getting/Setting value to gridview cells, you need to know the Row Index of Gridview, you can pass row index when you call JS function from gridview

<script language="javascript" type="text/javascript">
function update(rowIndexOfGridview) {
    var ri = rowIndexOfGridview; 
    var grd = document.getElementById('<%= GridView1.ClientID %>');

    CellValue = grd.rows[ri].cells[1].childNodes[0].value; // get
    grd.rows[ri].cells[2].childNodes[0].value = CellValue; assign
    ...........
    .............
}

<script language="javascript" type="text/javascript"> 
function Calculate() 
<br/>
{ 
<br/>
var grid = document.getElementById("<%=GridID.ClientID%>");
<br/> 
var sum = 0; <br/>
for (var i = 1; i < grid.rows.length; i++)<br/>
 { <br/>
var Cell = grid.rows[i].getElementsByTagName("input"); 
<br/>if (!Cell[4].value) {sum  += 0; } else { sum += parseFloat(Cell[4].value);} } 
<br/>
document.getElementById("<%=TextBox1.ClientID%>").value = sum; 
 }
<br/>
 </script>
------------------------------------------------------------------------



<asp:TemplateField HeaderText="Current payment" >
                            <ItemTemplate>
                                <asp:TextBox ID="cridnvalue" runat="server" Width="70px" BorderStyle="None" onkeyup="CalculateTax();" ></asp:TextBox>
                            </ItemTemplate>
                            <ItemStyle Width="120px" />
                        </asp:TemplateField>

You can try this one. I have used this and has no error.

<script language="javascript" type="text/javascript">
function update(rowIndexOfGridview) {
    var ri = rowIndexOfGridview; 
    var grd = document.getElementById('<%= GridView1.ClientID %>');

    var CellValue = grd.rows[ri].cells[1].childNodes[0].textContent); // get
    grd.rows[ri].cells[2].childNodes[0].textContent = CellValue; //assign
}
</script>