querystring n gv rows in javascript

query string in js: '<%=Request.QueryString["val"]%>';
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gridrows in js: Totalrows = parseInt('<%= this.gv1.Rows.Count %>');
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var rows = document.getElementById('gv').rows;
for(i=0;i <rows.length;i++)
{
   fd = rows[i].cells[4].innerText;
   rows[i].cells[4].style.display="none";
   rows[i].cells[8].style.display="none";
}

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<asp:Label ID="lblSno" runat="server" Text="<%# Container.DataItemIndex + 1%>"  />    ------------> to get the serial no for the gridview rows after bind the data (take the control to item template field of the grid)