Ian --
Thanks for your comment on my blog, drawing my attention to the WhatWG
spec for XMLHttpRequest. I like the fact that you've explicitly stated
that getResponseHeader/s() and responseText return whatever is available
so far in readyState 3.
On a related note, your spec is unambiguous that onreadystatechange() is
never to be called unless readyState actually changes.
It may be myth, but I was under the impression that existing
implementations might call onreadystatechange repeatedly for state 3, to
indicate download progress... This behavior (if it is actually
implemented) is useful to display a "loading..." animation and give the
end user feedback about the status of a long download.
Did you consider this and purposely reject it? I know that the common
XMLHttpRequest use case is for small downloads, so this would not be all
that commonly used... But if you decide to allow multiple calls to the
event handler for state 3, I suppose it would be useful to add a
bytesReceived property to the object...
David Flanagan
