send(undefined) and send("") fails.

[rjamesnw]

I'm loading test JSON data from a text file on a local web server (using IE) and thus don't need to send anything. Normally I send undefined or "", and it works using the native xmlHttpRequest object, but not with your wrapper.

According to the specification I found (http://xhr.spec.whatwg.org/#the-send()-method): "If data is null, do not include a request entity body and go to the next step." However, the data is not null when it's undefined or empty, and thus most browsers I've tested will send an empty request in these cases, AND return the response (or file in this case).