Actually it seems the number of sockets assigned to XHR requests is limited, and thus, this answers the question.
In the working draft, the question was inquired: What happens with multiple open calls? I am currently experiencing this aspect of the object, and it seems this can work only by using JavaScript closures. I wonder if the specification can state something to improve that. Another problem is that the order of request processing is not garanted. Can we change that? With values of onReadyStateChange?
