[whatwg] XMLHttpRequest

[David Flanagan]

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