客户端实现GridView全选全不选

<script type="text/javascript">
    function change(sender)
    {
        var checks = document.getElementById('<%=GridView1.ClientID %>');
        if(sender.checked)
        {
            alert(checks.rows.length.toString());
            for(var i=1;i<checks.rows.length;i++)
            {
                var ch = checks.rows[i].cells[0].getElementsByTagName("input")[0];
               ch.checked = true;
            }
        }
        else
        {
           for(var  i=1;i<checks.rows.length;i++)
            {
                checks.rows[i].cells[0].getElementsByTagName("input")[0].checked = false;
            }
        }
    }
    </script>

 

GridView：

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="True"
            DataKeyNames="sid" DataSourceID="SqlDataSource1">
            <Columns>
                <asp:TemplateField>
                    <HeaderTemplate>
                       <input ID="Checkbox1" runat="server" onclick="change(this);" type="checkbox" /></HeaderTemplate>
                    <ItemTemplate>
                        <asp:CheckBox ID="CheckBox2" runat="server" AutoPostBack="True"
                             />
                    </ItemTemplate>
                </asp:TemplateField>
                </Columns>
        </asp:GridView>