On Fri, Oct 5, 2012 at 8:00 AM, Ian Hickson <i...@hixie.ch> wrote: > This is specced. The UA is allowed to send the HTTP request (that's a > truism, of course, nothing stops the UA from sending any arbitrary HTTP > request at any time), but there's no in-DOM visible effect of that > request, because event loops don't process tasks for documents without > active browsing contexts, so the tasks that the "fetch" algorithm > generates never get executed. (A clever UA can notice this and delay > (forever) the HTTP requests, since the "fetch" algorithm allows you to > wait an arbitrary amount of time before doing the request.)
Note that you can append such an <img> to a different document later (e.g. the one that executes the script) so fetching it is probably smart. -- http://annevankesteren.nl/