On June 17, Mozilla Foundation released the long-awaited Firefox 3.0. The new version makes Firefox better than ever and arguably the best browser available.

As is usually the case with new versions, this latest release contains considerable performance improvements, mostly due to upgrades in the Gecko rendering engine. One thing that bothers me about a few Web sites is their massive use of JavaScript, which in some cases slows down interactivity to the point that simple tasks take forever and a day - sometimes I feel like I might have to go shave while waiting. OK, I'm exaggerating but hopefully you get the gist. One of the big performance improvements in Firefox 3.0 is that, according to Mozilla, JavaScript now runs nearly twice as fast as it does in Firefox 2.x, which means that a lot of Web 2.0 applications are going to be much more pleasant to use.

Another thing that formerly bothered me pertains to Firefox itself: Previous versions contained significant memory leaks. That's a big problem for those of us who keep numerous tabs open over long periods of time. To give you an example, I've run Firefox 2.x on a system with 2GB of RAM and had very little if anything else running on the desktop. Over a period of several days I might wind up having well over a dozen tabs open constantly. When I checked memory usage it wasn't unusual to see Firefox using 1GB of RAM or more! Fortunately Mozilla says that they've fixed "hundreds of memory leaks" in Firefox 3.0.

Mozilla also integrated a new "garbage collector" called XPCOM Cycle Collector, which helps release memory when it is no longer needed by various components. Third-party developers must integrate a bit of code into their modules for them to participate in garbage collection. For details on that process see the URL below.
http://developer.mozilla.org/en/docs/Interfacing_with_the_XPCOM_cycle_collector?rdfrom=http%3A%2F%2Fwiki.mozilla.org%2Findex.php%3Ftitle%3DInterfacing_with_the_XPCOM_cycle_collector%26redirect%3Dno

Aside from better performance and hopefully better memory usage, there are of course a number of significant security improvements. First there's a new site information window that pops up when you click the site name in the location bar. The window can display which site you're really connected to and whether the connection is encrypted using SSL. There's also new malware protection that gives the user a stern warning if they land on a known malware distribution site.

As you know, third-party plug-ins are a mainstay of Firefox and can be used to add untold amounts of very useful functionality. Like previous versions, Firefox 3.0 automatically checks to see if your plug-ins are up to date and can automatically install new versions; however, Firefox 3.0 will automatically disable plug-ins that are not delivered in a secure manner.

There is a significant security problem in Firefox 2.x (as well as other browsers) pertaining to JavaScript Object Notation (JSON), which is widely used as a sort of language-independent way of writing code. Earlier this year some security issues with JSON were discovered that might let intruders use JavaScript to perform malicious actions. This problem is now fixed with JavaScript 1.8 in Firefox 3.0. If you're interested in details of the vulnerability, go to the URL below, select JavaScript in the left pane, then Encapsulation, then JavaScript Hijacking: Ad Hoc Ajax.
http://www.fortify.com/vulncat/javascript/javascript_hijacking_ad_hoc_ajax.html

Other security improvements include antivirus software integration, parental controls, and better handling of cookies. And as is usually the case, there are numerous other non-security improvements that you'll probably enjoy.

For those of you seeking help in handling enterprise rollouts of Firefox, be sure to read my article "Enterprise Rollout and Management of Firefox," at the first URL below. To get an overview of other features in Firefox 3.0, read Paul Thurrott's article at the second URL below and Percy Cabello's review at the third URL below.
http://windowsitpro.com/article/articleid/96176
http://www.winsupersite.com/reviews/firefox3.asp
http://mozillalinks.org/wp/2008/03/firefox-3-beta-4-review

Finally, keep in mind that some sites do render differently in Firefox 3.0. To determine how your sites look in Firefox 3.0 (as well as 72 other Web browsers!) go to the URL below, where you'll find one of the most useful Web development tools available on the Internet today. The site can grab screen shots of any site using any of the supported browsers, so you get a direct look at your site that will immediately reveal any rendering problems.
http://browsershots.org