Check / Uncheck All Option in Grid view Using JavaScript

Grid View Coding:

<asp:GridView ID="grid_msprep" runat="server" AutoGenerateColumns="false" SkinID="gridviewSkin">

<Columns>

<asp:TemplateField HeaderText="S.No">

<ItemTemplate>

<%#Container.DataItemIndex +1 %>

ItemTemplate>

asp:TemplateField>

<asp:BoundField HeaderText="Journal" DataField="journal" />

<asp:BoundField DataField="article" HeaderText="Article" />

<asp:BoundField DataField ="volume" HeaderText="Volume" />

<asp:BoundField DataField ="issue" HeaderText="Issue" />                           

<asp:BoundField DataField ="category" HeaderText="Category" />

<asp:TemplateField HeaderText="Select">

<HeaderTemplate>

<asp:CheckBox ID="chkall" runat="server" onclick="checkAll(this,'grid_msprep','6')" Text="Check / UnCheck All" />

HeaderTemplate>

<ItemTemplate>

<asp:CheckBox ID="chkselect" runat="server" />

ItemTemplate>

asp:TemplateField>

Columns>

asp:GridView>

Java Script:

function checkAll(chkValue,gridId,chkBoxColumn)

{  

        var gridview = document.getElementById(gridId);       

        for(var i = 1;i < gridview.rows.length; i++)

        {

                gridview.rows[i].cells[chkBoxColumn].firstChild.checked = chkValue.checked ;           

        }

}