check all in grid view

Hi,
   when i check the check box in header template(gridview) only Enabled check boxes only should be Checked.i have some disabled row in grid view.it must be select only gridview check boxes.
my code is
<asp:GridView ID="EditableGridNew" runat="server">
<Columns>
<HeaderTemplate>
 <asp:CheckBox ID="chkSelect" runat="server" Text="select All" OnClick="selectAllD(this)" />
 </HeaderTemplate>
</Columns>
  </asp:GridView>



     function selectAllD(involker) {

        var inputElements = document.getElementsByTagName('input');
         for (var i = 0; i < inputElements.length; i++) {

             ...