JavaScript And DOM Performance
JavaScript/DOM Composite Score
Since JavaScript and DOM are basically inseperable, and in order to further cut down on the performance-oriented weighting in our final score, we're combining the JavaScript and DOM test results into a single composite score.
Chrome takes a strong lead under Windows 8 and Windows 7. Firefox comes in second place on both versions of Windows, finishing a ways behind the leader, but even further ahead of the third-place finisher. Even though it places slightly lower than IE10 in JavaScript, Opera moves up to third place due to its far stronger DOM scores. IE takes last place on both platforms, although IE10 performs notably better than IE9.
JavaScript
The JavaScript composite score is the geometric mean of the results from RIABench JavaScript, FutureMark Peacekeeper, Mozilla Kraken, and Google's modified version of Apple SunSpider. Neither IE9 nor Opera 12.10 will complete Google Octane, so that test is excluded.
Chrome steals the show in JavaScript performance once again, and without any Google benchmarks backing it up. Firefox earns second place, a ways behind Google Chrome. IE10 takes third place on Windows 8, while IE9 finishes last in Windows 7. Opera loses to IE10, but still beats IE9, placing fourth on Windows 8 and third under Windows 7. All four browsers demonstrate improved JavaScript scores in Windows 8, with IE10 showing a 40% increase over IE9.
Drill Down
The charts below contain the individual results for each JavaScript performance benchmark. The single RIABench score that is factored into the JavaScript composite is derived from the geometric mean of all nine RIABench JavaScript tests.
IE10 shows the most remarkable improvements in the Kraken and SunSpider benchmarks, while RIABench and Peacekeeper only reflect a marginal improvement over IE9. Chrome is the hands-down winner, as it has been for nearly the entire lifespan of Google's browser.
Seeing as how Internet Explorer 10 doesn't take the JavaScript crown, and Opera has been relatively stagnant in this discipline lately, hopefully Mozilla's upcoming IonMonkey engine can truly give Chrome a run for its money.
DOM (Document Object Model)
We use the DOM Core subsection of Mozilla's Dromaeo DOM tests to represent DOM performance in our final scoring. The Dromaeo results are an average of two iterations.
Naturally, Chrome also takes the lead in DOM core performance, followed closely by Firefox. Opera trails far behind in third place, with IE bringing up the rear. Unlike the JavaScript numbers, the DOM scores do not favor either version of Windows.