[XHR] Event processing during synchronous request

Is it defined how the browser should behave wrt calling 
unrelated event handlers in user code during synchronous
XHR requests? (with "unrelated" I refer to events that are
not related to the ongoing synchronous request itself)

I didn't find statements directly addressing this in
http://www.w3.org/TR/XMLHttpRequest/
or
http://www.whatwg.org/specs/web-apps/current-work/multipage/fetching-resourc
es.html
but maybe there are indirect relationships between
specification sections that I am missing?
Or maybe it's deliberately undefined?

I ask because Firefox behaves differently to the other
popular browsers, in that it triggers event handlers for
other asynchronous XHR requests while blocking for a
synchronous XHR request.

Thanks
Mike Wilson

Received on Sunday, 9 September 2012 16:34:20 UTC