I have a few web services that are accessed over public wifi connections and I think it would be a good idea to issue certificates to encrypt data, prevent MITM, and invalid impersonation (beyond what HTTPS provides).
Most of the client interaction I've seen with certificates involves a "fat client" and not so much with web sessions or javascript.
That being said,
What kind of standards should my javascript clients and web clients?
Will traditional clients be able to use the same web interface, or is a different standard appropriate (WS-*)?