Safari does not support server-push, a Netscape hack using Content-type: multipart/x-mixed-replace. Bugzilla, a bug tracking system, uses it in the query interface to display a "Please Wait" message. You can test that it does not work at bugzilla.mozilla.org. If you need to make it work, as I did in my internal Bugzilla, it only takes a small modification in Bugzilla source code:
exists $ENV{'HTTP_USER_AGENT'} &&
$ENV{'HTTP_USER_AGENT'} !~ /Safari/[Shown on two lines; enter as one with a space before the $ENV...]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030115065644812