1. A method for determining an event generator type of an interaction between a client and a web server, the method comprising: providing an effect to the client to invoke a change in event stream generation at the client wherein the affect is a message sent from the web server; receiving an event stream from the client; recording the affects as well as any expected reactions to the event stream; processing future events in the event stream to determine whether the expected reactions occurred within a timeout period; analyzing the event stream to determine a response to the effect; and determining an event generator type from the response; wherein the generator type is set based on at least one of: whether an expected human-dependent reaction has occurred and if an expected human-dependent reaction has not occurred.