One of the most prominent advantages of this latest version is on the increase in its JavaScript engine. Firefox 9 has a JavaScript engine that is able to increase browser speed by 20 to 30 percent.
During this time, Internet Explorer (IE) and Google Chrome has an advantage in JavaScript, but with Firefox 9, it has begun to equal advantage. So, if you've been using IE and Chrome as its Javascript factors, from now on you have to glance at this latest version of Firefox.
The majority of crashes are often experienced by users of Firefox mostly occur due to errors in the plugin Adobe Flash, Apple QuickTime, or Microsoft Silverlight. In the latest Mozilla Firefox 9, if one of the plugins that use crashor freeze, it will not affect the overall performance of the browser. All you need to do is reload the page to restart the plugin and try again.
Along with a bunch of bug fixes and stability, as well as an increase in overall speed, Firefox 9 for Mac OS X now allows for the "two finger swipe navigation".