The official Summer 2009 Javascript speed test results have been posted!   Check them out under the “Test Results” section of the page.  The conclusion: “Safari has taken the lead by performing about twice the speed of its nearest competitors, Chrome and Firefox.  Opera, the once champion of the speed test, has fallen from its throne to the second-to-last position.  Perhaps the most surprising is how much worse IE8 fared relative to its competitors — it was 2-3 times slower, but now is performing almost five times slower.”