I'm getting this slow script warning after 10 seconds on that site: A script on this page may be busy, or it may have stopped responding. You can stop the script now, or you can continue to see if the script will complete. Script: http://www.wonderword.com/media/system/js/mootools.js:18 This regressed between 2010-09-11 and 2010-09-13. That's when JaegerMonkey was merged with Mozilla-Central.