AJAX-- access BackColor And ForeColor properties of the TextBox

TextBox has BackColor  And  ForeColor properties.  It's easy to control/access these properties in Server-side code.  My question:

How can I access these properties in client-side code using AJAX or/and javascript ???

<asp:TextBox ID="txtName" runat="server"></asp:TextBox>

   <script type="text/javascript">

            var myName = document.getElementById('txtName');

            How can I access BackColor  And  ForeColor HERE???

    </script>


Thanks