flowjs/flow.js — pull request #20 by clicktrend (2014-04-28 22:49:10+00:00)
Title: async request for cors

I faced this error with FF 28.0

>[Exception... "A parameter or an operation is not supported by the underlying object" code: "15" nsresult: "0x8053000f (InvalidAccessError)" location: ""]

while trying to make an CORS request.

Similar problem is described here http://stackoverflow.com/questions/16677893/evil-firefox-error-a-parameter-or-an-operation-is-not-supported-by-the-under

I solved it adding 3rd parameter for async in your code line 1370

>this.xhr.open(method, target, true);