The Shumway interpreter and JIT work in other browsers, but the installable extension to replace the Flash plugin as the default SWF handler is currently Firefox-only. But pull requests are welcome! :)

You can try Shumway in other browsers without the extension at the project website:

http://www.areweflashyet.com/shumway/

The SpiderMonkey team's "Are We Fast Yet?" website also includes some AS3 benchmarks running in Shumway on Firefox, Chrome, and Safari:

http://arewefastyet.com/#machine=28&view=breakdown&suite=shu...