class ActiveSupport.Request
Description
Supports an indentical API to Prototype's Ajax.Request/Response, but does not include handling / onException callbacks or Ajax.Responders.
You can mimic Ajax.Responder functionality with ActiveEvent:
//only needs to be done once per app, but not enabled by default
ActiveEvent.extend(ActiveSupport.Request);
ActiveSupport.Request.observe('onComplete',function(request,response,header_json){});


