Show Number of Selected Checkbox in GridView Footer Row using JQuery in ASP.Net

@AmanSingh, replace your script with this

<script type="text/javascript">
       $("[id*=chkHeader]").live("click", function () {
        var chkHeader = $(this);
        var grid = $(this).closest("table");
        $("input[type=checkbox]", grid).each(function () {
            if (chkHeader.is(":checked")) {
                $(this).attr("checked", "checked");
                $("td", $(this).closest("tr")).addClass("selected");
            } else {
                $(this).removeAttr("checked");
                $("td", $(this).closest("tr")).removeClass("selected");
            }
        });
        $('[id*=lblFooterTotal]').html($("[id*=chkRow]:checked").length);
    });
    $("[id*=chkRow]").live("click", function () {
        var grid = $(this).closest("table");
        var chkHeader = $("[id*=chkHeader]", grid);
        if (!$(this).is(":checked")) {
            $("td", $(this).closest("tr")).removeClass("selected");
            chkHeader.removeAttr("checked");
        } else {
            $("td", $(this).closest("tr")).addClass("selected");
            if ($("[id*=chkRow]", grid).length == $("[id*=chkRow]:checked", grid).length) {
                chkHeader.attr("checked", "checked");
                             }
        }
         $('[id*=lblFooterTotal]').html($("[id*=chkRow]:checked").length);
    });
</script>

    <label id="lblFooterTotal"></label>
    <asp:GridView ID="GridView1" runat="server" HeaderStyle-BackColor="#3AC0F2"
    HeaderStyle-ForeColor="White" AutoGenerateColumns="false">
    <Columns>
        <asp:TemplateField>
            <HeaderTemplate>
                <asp:CheckBox ID="chkHeader" runat="server" />
            </HeaderTemplate>
            <ItemTemplate>
                <asp:CheckBox ID="chkRow" runat="server" />
            </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField DataField="Name" HeaderText="Name" ItemStyle-Width="150" />
        <asp:BoundField DataField="Country" HeaderText="Country" ItemStyle-Width="150" />
        <asp:TemplateField>
            <FooterTemplate>
            </FooterTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>
<hr />
<asp:GridView ID="GridView2" runat="server" HeaderStyle-BackColor="#3AC0F2"
    HeaderStyle-ForeColor="White" AutoGenerateColumns="false">
    <Columns>
        <asp:TemplateField>
            <HeaderTemplate>
                <asp:CheckBox ID="chkHeader" runat="server" />
            </HeaderTemplate>
            <ItemTemplate>
                <asp:CheckBox ID="chkRow" runat="server" />
            </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField DataField="Name" HeaderText="Name" ItemStyle-Width="150" />
        <asp:BoundField DataField="Country" HeaderText="Country" ItemStyle-Width="150" />
    </Columns>
</asp:GridView>
<hr />
<asp:GridView ID="GridView3" runat="server" HeaderStyle-BackColor="#3AC0F2"
    HeaderStyle-ForeColor="White" AutoGenerateColumns="false">
    <Columns>
        <asp:TemplateField>
            <HeaderTemplate>
                <asp:CheckBox ID="chkHeader" runat="server" />
            </HeaderTemplate>
            <ItemTemplate>
                <asp:CheckBox ID="chkRow" runat="server" />
            </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField DataField="Name" HeaderText="Name" ItemStyle-Width="150"/>
        <asp:BoundField DataField="Country" HeaderText="Country" ItemStyle-Width="150"/>
    </Columns>
</asp:GridView>