LearnBoost/engine.io-client — pull request #49 by mixu (2012-08-31 22:46:31+00:00)
Title: Fix cross-protocol-cross-domain requests on IE8, IE9

IE's XDomainRequest cannot do requests that go from HTTPS to HTTP or HTTP to HTTPS, so fall back to JSONP.

Similar to https://github.com/LearnBoost/socket.io-client/blob/master/lib/transports/xhr.js#L188