Pressing the button at <http://vesna.yandex.ru/cgi-bin/vesna> should each time result in new random text being displayed. This doesn't work if one is behind a caching proxy, because the server sends no proxy control HTTP headers, and the URL is always the same in Safari.
Firefox and WinIE correctly append a question mark to the URL when submitting the form, which avoids caching: <http://vesna.yandex.ru/cgi-bin/vesna?>.
<form name="filo" method="get" action="/cgi-bin/vesna">
<input type="submit" value="Continue"/>
Created attachment 7393 [details]
Firefox 3.5.3 does not add the ? when the form has no form data.
Maybe they changed since this bug is pretty old.
The reason why I am bring this up again is that this is one of the reasons for bug 20342. That test submits to a fragment (#a) with an empty form but since a '?' is added the URL is not the same and therefore reloads from the server making which causes the test to infinitely reload. (There are more problems with that layout test.)
IE9 does the same thing as Firefox. However, the WebKit behavior follows standards. I will add a longer comment explaining my interpretation of the standards to a bug that basically asks to get this change reverted.