Mac users can grab the latest beta from the Opera website, the Windows beta 2 release remains, for now, an FTP download.

While the Opera web browser may not have the largest market share, it is the source off many browser innovations. Tabbed browsing got its start in Opera, and the browser was one of the first to broadly support emerging standards like HTML5 and CSS 3.

We took a detailed look at Opera 10.5 when the first beta was released for Windows and found that, aside from some interface design changes, the big news in this release is speed. This is largely due to the inclusion in this release of Opera’s new Carakan JavaScript engine, which boosts the browser’s performance on webapps considerably. Opera 10.5 is noticeably faster than its predecessors and even beat Firefox 3.6 and Google Chrome in our informal testing.

The second beta release is primarily a slew of bug fixes and doesn’t offer much in the way of new features. Still, if you’ve been enjoying the first beta, this release should make the experience a little more stable. And now Mac users can get into the party as well, though 10.5 beta 2 is unfortunately only available for Windows users. Mac users are only caught up as far as Opera 10.5 beta 1.

Also worth mentioning is that native HTML5 video is working in both Windows and Mac version of Opera 10.5 beta. Opera joins Firefox as the second browser to go with the Ogg Theora codec for native web video.

See Also:

• Is Opera 10.5 the ‘Fastest Browser on Earth?’ Maybe
• Opera Looks to the Future With Latest Browser Preview
• Opera CTO Sees Open Video Formats as Key to Web’s Future

This latest pre-release build of Firefox 3.6 has seen numerous bug fixes since beta 5, including the usual improvements in browser performance and stability. Existing beta users should have received Firefox 3.6rc1 over the weekend. If not, head to the Help menu and choose “Check for Updates.” If you’re not involved in the beta testing yet, you can download Firefox 3.6rc1 from Mozilla’s website.

Mike Beltzner, who heads Firefox development at Mozilla, tells Webmonkey that the final version of the browser should be released, “in the next couple of weeks.”

So, this will likely be the final pre-release version of Firefox 3.6. Beltzner remains optimistic that there will be no more changes, but a second release candidate isn’t out of the question.

The RC stage is when the code is fully complete, and it’s usually the point where web designers and add-on developers can confidently begin testing their creations to make sure they’ll work as intended once the final release arrives. Most start their testing early, however — Mozilla reports that over 75 percent of Firefox Add-ons have now been upgraded to be compatible with Firefox 3.6 betas, including the ever-popular Greasemonkey.

Sadly, two of our favorite web development add-ons, Yahoo’s YSlow and Google’s recently released Page Speed tool have yet to update for Firefox 3.6. If you’d like to help out the developers of your favorite add-on, grab the Add-on Compatibility Reporter, which, among other things, allows you to run add-ons that haven’t yet been updated.

Given that this is a release candidate, there are no flashy new features to speak of. But there have been some final bug fixes added since the fifth beta was released in December 2009.

See Also:

• Firefox 3.6 Nearly Complete, Fifth Beta Available Now
• Firefox 3.6 Beta 3 Gains Security Features, Loses Windows 7 Integration
• Chrome Extensions Are Cool, But They Can’t Match Firefox

Firefox 3.6, currently in the final beta-release stages, will arrive in the first quarter of 2010, according to Mozilla Wiki. The slight delay is having a ripple effect, however, because future Firefox releases have been rescheduled as well. Mozilla has already pushed back its road map for both Firefox 3.7 and 4.0.

Once Firefox 3.6 is out the door, Firefox 3.7 (a fairly minor, incremental release) shouldn’t be too far behind, but we may have to wait until 2011 before the next major revision roles around. According to recent Mozilla meeting notes, Firefox 4.0 won’t come around until late 2010 or early 2011.

Despite the distant release dates, Mozilla is already hard at work on both Firefox 3.7 and 4.0. Judging by the current schedule, Firefox 3.7 will bring a few updates and possibly a slightly tweaked theme, but we’ll have to wait for 4.0 before we see any big changes and new features.

So what can you expect in Firefox 4.0 when it finally does arrive? Well, on the new features side of things, most of the answers lie in Mozilla Labs. JetPack, which was recently updated to version 0.7, is on the short list, as is Weave, a tool that syncs your Firefox installations across PCs. There’s even a chance that some elements of Ubiquity, the “command-line for the web,” might be integrated into the Firefox 4.0 Awesomebar.

Under the hood, Firefox 4.0 will feature an update to the Gecko rendering engine, with more HTML5 and CSS 3 support as well as speed improvements. One major goal is to reduce startup times by 25 percent.

But the biggest change will likely be the introduction of Electrolysis.

Electrolysis is the name of a Mozilla project that will split Firefox into multiple processes — one for the user interface, one for plug-ins and one for each tab. Similar functionality is already being seen in other clients, like Google Chrome. As in Chrome, a crash in a single tab will no longer be able to bring down the entire browser. Also, we can expect Electrolysis to make Firefox faster and more stable overall.

Firefox 4.0 will also likely feature a revamped look, possibly with a Chrome-like “tabs on top” user interface and a new, more feature-rich “home tab.” If you’d like to have a say in the look and feel of future Firefox release, check out the current Mozilla design challenge.

The addition of some Chrome-like features is no coincidence. Chrome’s arrival and its subsequent innovations have accelerated developments in the browser market. All the attention being paid to the younger browser puts Mozilla in danger of losing some of the user base it has worked so hard to capture over the last five years. The potential 2011 release date of Firefox 4.0 means that before that next big Firefox upgrade arrives, there will likely be a significant update to Google Chrome, a new version of Safari and possibly even a release of Internet Explorer 9.

See Also:

• Firefox 3.6 Nearly Complete, Fifth Beta Available Now
• Help Mozilla Improve Firefox’s New ‘Home’ Tab
• Mozilla’s JetPack Gets Ready to Take on Chrome Extensions
• Chrome Extensions Are Cool, But They Can’t Match Firefox

This pre-alpha release is currently only available for Windows and Mac OS X users. Opera says a Linux version will be released soon. If you’d like to test out Opera 10.5, download links can be found at the bottom of the Opera Labs announcement page.

Much of Opera 10.5′s speed improvements come from the revamped JavaScript engine, known as Carakan, which Opera claims is up to seven times faster than the engine in the current shipping version, Opera 10. It’s worth noting that the Mac version is not nearly as far along as the Windows release, so Mac users may not notice a dramatic speed boost in this early release.

Also new under the hood is support for CSS3 transitions and transforms, which means that the cool CSS 3 transform tricks we told you about last week will work in this version of Opera (note that you’ll need to add the Opera flag to your CSS code, for example, -o-transition-property).

The pre-alpha release of Opera 10.5 also features a new graphics engine that can take advantage of hardware acceleration (when it’s available) to render SVG graphics. Given the possibility of very complex graphics thanks to HTML5′s canvas tag, we expect to see more emphasis on graphics engine in the coming year (think of hardware-accelerated graphics as a sequel to the JavaScript engine contests of recent months).

Opera is also one of the last browsers to jump on the private-browsing-mode bandwagon, but it is finally here in this release.

While the speed boosts in Opera 10.5 are noticeable, particularly on JavaScript-intensive sites and web apps, Opera 10.5 is very much a work in progress and lacks some very basic features — like printing in the Mac version. Also missing is support for Opera’s Unite web server tools.

As you would expect from the pre-alpha designation Opera 10.5 is also somewhat unstable, but if you’d like to test out the latest release, head over to the Opera Labs page and grab a copy.

See Also:

• Opera 10 Arrives: Turbo, New Tabs and a Fresh Coat of Paint
• Faster, Sleeker Opera 10 Is Built for Better Web Apps
• Opera Unite Puts a Web Server in Your Web Browser

Firefox 3.6 has seen more than 100 bugfixes since beta 4, including improvements in Firefox’s performance, stability, and security. If you’d like to take beta 5 for a spin, head over to the Mozilla downloads page or just wait for your current Firefox 3.6 beta to automatically update.

Five betas is an unusually high number for a Firefox release, but the latest package clears most of the remaining blocking bugs. This means the final release of Firefox 3.6 is likely just around the corner.

Given that we’re so close to the final release, Firefox 3.6 beta 5 doesn’t contain any significant new features. It does, however, bring some very welcome bug fixes, including a couple of annoying scrolling bugs we’ve had to deal with in previous beta releases.

This release also fixes a bug that would occasionally cause Firefox to crash on the Twitter login page, and worse, would expose passwords in plain text.

The other big of good news for this release is that Add-on developers are getting ready for the final release of Firefox 3.6. Mozilla reports that over 70 percent of Firefox Add-ons have now been upgraded to be compatible with Firefox 3.6 Beta, including the ever-popular Greasemonkey.

Sadly two of our favorite web development add-ons, Yahoo’s YSlow and Google’s recently released Page Speed tool have yet to update for Firefox 3.6. If you’d like to help out the developers of your favorite add-on, grab the Add-on Compatibility Reporter, which, among other things, allows you to run add-ons that haven’t yet been updated.

See Also:

• Firefox 3.6 Beta 3 Gains Security Features, Loses Windows 7 Integration
• Firefox 3.6 Beta 1 Arrives: More Speed, Better Video, New Tab Tricks
• Chrome Extensions Are Cool, But They Can’t Match Firefox
• New Google Tools Help Speed Up Your Website

Firefox 3.6 beta 2, released Wednesday, brings 190 more bug fixes to the table and offers the same performance boosts we saw in the first beta release. Firefox 3.6 also includes a number of new features like support for Personas, native tab-previews for Windows 7 and Web Open Font Format support for developers looking to use new fonts on their sites.

For a more in-depth look at what’s coming in the next version of Firefox — due to arrive in final form sometime before the end of 2009 — have a look at our coverage of the first beta release.

While Firefox 3.6 is still a beta release, if you’d like to test out the new features you can grab a copy from Firefox beta page. Also, if you’re running beta 1, you’ll notice Firefox probably gave you an alert as soon as beta 2 was ready.

So far, we haven’t noticed any show-stopping bugs in beta 2, but keep in mind that most extensions haven’t been updated to work with this release. That said, a few of our favorites do indeed work, notably AdBlock Plus and Firebug, though in both cases you’ll need to make sure you have the latest versions of the add-ons.

You can help out add-on developers by grabbing the Add-on Compatibility Reporter, which will run all your extensions even if they haven’t been updated. Any resulting bugs or strange behaviors can be easily reported to the developers through the Add-ons Manager.

See Also:

• Firefox 3.6 Beta 1 Arrives: More Speed, Better Video, New Tab Tricks
• Mozilla Throws Its Weight Behind Improving Web Type, Adopts WOFF for Firefox
• Mozilla Readies Windows 7 Support for Firefox 3.6

On the surface, it looks like incremental performance upgrade from the current version, Firefox 3.5, which was released in June. But anyone spending a great deal of time in JavaScript-heavy web apps — which these days is most of us — will notice faster page loads thanks to improvements to the browser’s rendering engine. This new beta also has better support for the latest emerging web standards like HTML5 and CSS3, better native video playback, a new plugin updating mechanism and some new tab behaviors.

If you’d like to test Firefox 3.6 beta 1, head over to the Mozilla downloads site and grab a copy. The final version is set to arrive sometime before the end of 2009. The relatively short six-month wait between upgrades is evidence of Mozilla’s promise to speed up its release schedule.Mozilla has slightly tweaked the way beta releases work. Now, if you download the beta, it will automatically upgrade to the release candidate, then the final release when it arrives.

One of the first things you’ll notice in the new beta is the performance boost. Firefox 3.6 features some tweaks to TraceMonkey, Mozilla’s own engine for rendering JavaScript on web pages . The new version of TraceMonkey in this release has been optimized to work within Firefox, meaning that, not only is TraceMonkey being used to speed up web apps, it’s now available to speed up Firefox UI elements written in JavaScript. That change should make the Firefox interface slightly snappier, and when combined with the new version of Gecko, Firefox’s core rendering engine, expect to some noticeable improvements in Firefox’s performance.

Mozilla hasn’t made any specific claims of speed boosts in Firefox 3.6, but in our testing, JavaScript-heavy sites like FriendFeed, Facebook and Gmail loaded faster, and the browser’s initial start-up time was much better than with Firefox 3.5 (especially if you’re reopening a large number of tabs).

But as with previously releases, Firefox loves to gobble up RAM. Perhaps not as much as pre-3.0 releases, but 3.6 still demands more overhead than Safari and Opera on our Macbook Pro.

The full screen support for native video embeds, which we told you about earlier this year, has arrived with the new beta. Just right click a video embedded using the HTML5 video tag and you’ll see a new menu item for full screen playback.

On the user interface front, the default tab behavior has been tweaked slightly. Opening a link by CMD-clicking now places the new tab right next to the currently open tab. That’s a significant change from previous versions, where the default behavior was to open new tabs at the far right side of the current window. Indeed if you just open a blank tab, it will be placed on the far right, but opening a link in a new tab will not.

Quite frankly, we found the new behavior frustrating and confounding — so much so that we’re unsure whether to call it a feature or a bug. Fortunately, there’s an easy way to get the old behavior back: head toabout:config and change the tabs.insertRelatedAfterCurrent setting to false.

Note: See Wired’s How-To Wiki entry on customizing Firefox 3.6 to add your own tips.

Also new on the tab front are the long-awaited preview thumbnails in Firefox’s built-in tab switcher, which have finally arrived — sort of. The tab previews have been in the works for quite some time and sadly, enabling the previews will still require a trip to about:config (set browser.ctrlTab.previews to true). Hopefully, by the time the final release arrives, preview icons on Firefox’s tab switcher will be turned on by default.

Firefox’s new tab-switching interface. Click the image for a larger view.

Firefox 3.6 beta 1 also supports Windows 7′s Aero Peek tab previews — the page and tab previews available in the Windows 7 task bar. As with other Win 7 apps, hovering your mouse over Firefox’s task bar icon will pop up previews of all your Firefox windows and tabs, making it quicker and easier to navigate between them.

Firefox 3.6 beta 1 brings built-in support for lightweight themes, which Mozilla calls Personas. Personas has been around for a while (you can even sync them through Weave), but previously installing Personas required a separate extension to manage them.

As of the new beta, Personas can be installed right out of the box, allowing you to tweak and theme Firefox as you’d like. Although Personas don’t offer quite the options of a full fledged theme, they’re much easier to create and install. If you’d like to try out some custom themes, head over to the Persona site.

The beta also features a new plug-in update mechanism which will warn you when, for example, your Flash plug-in is out of date and possibly vulnerable to attack.

Also new under the hood is the Web Open Font Format (WOFF) support we mentioned last month, as well as the new about:support page which offers a simple place to look up all the pertinent information about the current Firefox installation, including a list off installed extensions, any user-modified preference setting, links to installed plug-ins and other configuration details.

Read the full release notes if you want to see more about the nitty gritty bits.

As with any beta Firefox release, don’t expect all your favorite extensions to work right now. In our testing, Ad Block Plus and Weave were the only of our half dozen extensions that worked out of the box. You can help out add-on developers by grabbing the Add-on Compatibility Reporter, which will run all your extensions even if they haven’t been updated. Any resulting bugs or strange behaviors can be easily reported to the developers through the Add-ons Manager.

See Also:

• Mozilla Throws Its Weight Behind Improving Web Type, Adopts WOFF for Firefox
• Weave Adds Personas to its Bag of Firefox Syncing Tricks
• Mozilla Readies Windows 7 Support for Firefox 3.6
• Troubleshooting Firefox Gets Easier With New ‘About:Support’ Page