There seems to be a problem with the xhr polling as it sets withCredentials to true if withCredentials exits in xhr (This always happens?).
As the engine.io-server does not depend on the extra information granted by withCredentials (Cookies e.g.), should not this be set to false by default? And/or should there be a configuration for it?
Line 226-229 in polling-xhr.js
// ie6 check
if ('withCredentials' in xhr) {
xhr.withCredentials = true;
}