title: Allow user to cancel upload javascript, xmlhttp request
body: <p>I have an xmlhttprequest that is posting to a webservice and is linked to the user uploading a potentially large file and I would like to be able to cancel the request based on user input.  I see that the xmlhttprequest object has an abort function but as far as I can tell by watching the network tab in chrome, calling that does not actually stop sending data and free up the users bandwidth, it only affects the events </p>