It's not happened to me (Opera 9.63 x86_64 Linux) but I have a suspicion for the possible cause: The up/down arrows are anchor tags to the vote URL, so if you h

It's not happened to me (Opera 9.63 x86_64 Linux) but I have a suspicion for the possible cause: The up/down arrows are anchor tags to the vote URL, so if you had JavaScript disabled, the behaviour you describe would be expected. (it probably should redirect back to the page you were looking at, from a usability POV...) The async version uses the onclick event attribute to call the vote() JS function, which returns false to cancel the anchor click navigation after dynamically generating a new image with the vote URL as src attribute. If anything in vote() throws an exception, vote won't return false to cancel the navigation, so you get taken to the (blank) non-JS vote page. I can't see anything at first glance that would throw an exception, however.