Using Firefox 23 or higher (Beta, Aurora and Nightly) on OS X 10.6.8, when I try open the Google login page, Firefox hangs and use almost 100% of the cpu. I tried: * safe mode * the reset the reset Firefox button in "about:support" * a new Firefox profile * deleting ~/Library/Application Support/Firefox/ and completely re-installing Firefox. I also read that page: https://support.mozilla.org/en-US/products/firefox/fix-problems and I tried all the relevant suggestions. The only way I was able to access the login page was to revert to Firefox 22. The same problem also happens with the mdn search result page ( https://developer.mozilla.org/en-US/search?q=test ), but I haven't found any other problematic pages yet.