Firefox 3 Beta 4 is a developer preview release of Mozilla's next generation Firefox browser and is being made available for testing purposes only .

These beta releases are targeted to Web developers and our testing community to gain feedback before advancing to the next stage in the release process. The final version of Firefox 3 will be released when we qualify the product as fully ready for our users. Users of the latest released version of Firefox should not expect their add-ons to work properly with this beta.

Please see below for an extensive list of features and enhancements found in Firefox 3 Beta 4, as well as known issues and frequently asked questions . As always, we appreciate your feedback either through this feedback form or by filing a bug in Bugzilla .

1. Windows
   • UK Version
   • US Version
2. Linux
   • UK Version
   • US Version
3. Mac OS X
   • UK Version
   • US Version

Bear in mind this is still a Beta release and is not fully released yet. Not all add-ons will work with it. See the full Release Notes here

according to the people at ubuntu it is great and the most stable browser yet ( on unix platform)

What's New In Firefox 3?

Firefox 3 is based on the Gecko 1.9 Web rendering platform, which has been under development for the past 31 months. Building on the previous release, Gecko 1.9 has more than 12,000 updates including some major re-architecting to provide improved performance , stability, rendering correctness, and code simplification and sustainability. Firefox 3 has been built on top of this new platform resulting in a more secure , easier to use , more personal product with a lot more under the hood to offer website and Firefox add-on developers. [Improved in Beta 4!] Firefox 3 Beta 4 includes more than 900 enhancements from the previous beta, including drastic improvements to performance and memory usage, as well as fixes for stability, platform enhancements and user interface improvements. Many of these improvements were based on community feedback from the previous beta. More Secure One-click site info: Click the site favicon in the location bar to see who owns the site and to check if your connection is protected from eavesdropping. Identity verification is prominently displayed and easier to understand. When a site uses Extended Validation (EV) SSL certificates, the site favicon button will turn green and show the name of the company you're connected to. ( Try it here! ) Malware Protection: malware protection warns users when they arrive at sites which are known to install viruses, spyware, trojans or other malware. ( Try it here! ) New Web Forgery Protection page: the content of pages suspected as web forgeries is no longer shown. ( Try it here! ) New SSL error pages: clearer and stricter error pages are used when Firefox encounters an invalid SSL certificate. ( Try it here! ) Add-ons and Plugin version check: Firefox now automatically checks add-on and plugin versions and will disable older, insecure versions. Secure add-on updates: to improve add-on update security, add-ons that provide updates in an insecure manner will be disabled. Anti-virus integration: Firefox will inform anti-virus software when downloading executables. Vista Parental Controls: Firefox now respects the Vista system-wide parental control setting for disabling file downloads. Effective top-level domain (eTLD) service better restricts cookies and other restricted content to a single domain. Better protection against cross-site JSON data leaks . Easier to Use Easier password management: an information bar replaces the old password dialog so you can now save passwords after a successful login. Simplified add-on installation: the add-ons whitelist has been removed making it possible to install extensions from third-party sites in fewer clicks. [Improved in Beta 4!] New Download Manager: the revised download manager makes it much easier to locate downloaded files, and you can see and search on the name of the website where a file came from. Your active downloads and time remaining are always shown in the status bar as your files download. Resumable downloading: users can now resume downloads after restarting the browser or resetting your network connection. [Improved in Beta 4!] Full page zoom: from the View menu and via keyboard shortcuts, the new zooming feature lets you zoom in and out of entire pages, scaling the layout, text and images, or optionally only the text size. Your settings will be remembered whenever you return to the site. Podcasts and Videocasts can be associated with your media playback tools. Tab scrolling and quickmenu: tabs are easier to locate with the new tab scrolling and tab quickmenu. Save what you were doing: Firefox will prompt users to save tabs on exit. Optimized Open in Tabs behavior: opening a folder of bookmarks in tabs now appends the new tabs rather than overwriting. Location and Search bar size can now be customized with a simple resizer item. Text selection improvements: multiple text selections can be made with Ctrl/Cmd; double-click drag selects in "word-by-word" mode; triple-clicking selects a paragraph. Find toolbar: the Find toolbar now opens with the current selection. Plugin management: users can disable individual plugins in the Add-on Manager. [Improved in Beta 4!] Integration with Vista: Firefox now has Vista-specific icons, and uses native user interface widgets in the browser and in web forms. [Improved in Beta 4!] Integration with the Mac: the new Firefox theme makes toolbars, icons, and other user interface elements look like a native OS X application. Firefox also uses OS X widgets and spell-checker in web forms and supports Growl for notifications of completed downloads and available updates. A combined back and forward control make it even easier to move between web pages. [Improved in Beta 4!] Integration with Linux: Firefox's default icons, buttons, and menu styles now use the native GTK theme. More Personal Star button: quickly add bookmarks from the location bar with a single click; a second click lets you file and tag them. Tags: associate keywords with your bookmarks to sort them by topic. [Improved in Beta 4!] Location bar & auto-complete: type in all or part of the title, tag or address of a page to see a list of matches from your history and bookmarks; a new display makes it easier to scan through the matching results and find that page you're looking for. Results are returned according to their frecency (a combination of frequency and recency of visits to that page) ensuring that you're seeing the most relevant matches. An adaptive learning algorithm further tunes the results to your patterns! Smart Bookmarks Folder: quickly access your recently bookmarked and tagged pages, as well as your more frequently visited pages with the new smart bookmarks folder on your bookmark toolbar. Places Organizer: view, organize and search through all of your bookmarks, tags, and browsing history with multiple views and smart folders to store your frequent searches. Web-based protocol handlers: web applications, such as your favorite webmail provider, can now be used instead of desktop applications for handling mailto: links from other sites. Similar support is available for other protocols (Web applications will have to first enable this by registering as handlers with Firefox). Download & Install Add-ons: the Add-ons Manager (Tools > Add-ons) can now be used to download and install a Firefox customization from the thousands of Add-ons available from our community add-ons website . When you first open the Add-ons Manager, a list of recommended Add-ons is shown. Easy to use Download Actions: a new Applications preferences pane provides a better UI for configuring handlers for various file types and protocol schemes. Improved Platform for Developers New graphics and font handling: new graphics and text rendering architectures in Gecko 1.9 provides rendering improvements in CSS, SVG as well as improved display of fonts with ligatures and complex scripts. Color management: (set gfx.color_management.enabled on in about :config and restart the browser to enable.) Firefox can now adjust images with embedded color profiles. Offline support: enables web applications to provide offline functionality (website authors must add support for offline browsing to their site for this feature to be available to users). A more complete overview of Firefox 3 for developers is available for website and add-on developers. Improved Performance [Improved in Beta 4!] Speed: improvements to our JavaScript engine as well as profile guided optimizations have resulted in significant improvements in performance. Compared to Firefox 2, web applications like Google Mail and Zoho Office run twice as fast in Firefox 3 Beta 4, and the popular SunSpider test from Apple shows improvements over previous releases. [Improved in Beta 4!] Memory usage: Several new technologies work together to reduce the amount of memory used by Firefox 3 Beta 4 over a web browsing session. Memory cycles are broken and collected by an automated cycle collector, a new memory allocator reduces fragmentation, hundreds of leaks have been fixed, and caching strategies have been tuned. Reliability: A user's bookmarks, history, cookies, and preferences are now stored in a transactionally secure database format which will prevent data loss even if their system crashes.

Downloading and Installing

System Requirements Before installing, make sure your computer meets the system requirements . Downloading Firefox 3 Beta 4 Mozilla provides Firefox 3 Beta 4 for Windows, Linux, and Mac OS X in a variety of languages. You can get the latest version of Firefox 3 Beta 4 here . For builds for other systems and languages not provided by Mozilla.org, see the Contributed Builds section at the end of this document. Installing Firefox 3 Beta 4 Please note that installing Firefox 3 Beta 4 will overwrite your existing installation of Firefox on Mac OS X and Linux. On Windows, Firefox 3 Beta 4 installs in a new folder. For all systems, you won't lose any of your bookmarks or browsing history, but some of your extensions and other add-ons might not work until updates for them are made available. Removing Firefox 3 Beta 4 You can remove Firefox 3 Beta 4 through the Control Panel in the Start Menu on Windows, by removing the Firefox application on OS X, or by removing the firefox folder on Linux. Removing Firefox 3 Beta 4 won't remove your bookmarks, web browsing history, extensions or other add-ons. This data is stored in your profile folder , which is located in one of the following locations depending on your operating system: Windows Vista Users\\AppData\Roaming\Mozilla\Firefox Windows 2000, XP, Server 2003 Documents and Settings\\Application Data\Mozilla\Firefox Mac OS X ~/Library/Application Support/Firefox Linux and Unix systems ~/.mozilla/firefox Any version of Firefox that you install after removing Firefox 3 Beta 4 will continue to use the data from this profile folder. Extensions and Themes Extensions installed under previous versions of Firefox may be incompatible and/or require updates to work with Firefox 3 Beta 4. Please report any issues to the maintainer of the extension. When you install Firefox 3 Beta 4 all of your Extensions and Themes will be disabled until Firefox 3 Beta 4 determines that either a) they are compatible with the Firefox 3 Beta 4 release or b) there are newer versions available that are compatible. Known Issues This list covers some of the known problems with Firefox 3 Beta 4. Please read this before reporting any new bugs. All Systems Windows Live Mail will not work; users must use Hotmail Classic Mail ( bug 396259 ) GMail (new version) conversation labels appear on their own row in the message list, and names don't show in the contacts manager ( bug 415252 ) The "Report Web Forgery" menu item doesn't work (see bug 420677 ) Firefox will not ask users if they wish to change a stored password (see bug 421058 ) MathML does not render properly in Firefox 3 Beta 4 ( bug 363240 and bug 413115 ) The new Location Bar, Add Bookmark dialog, and Download Manager information popup behave inconsistently with Window-Eyes. JAWS 8.0 or better is recommended for this beta. ( bug 393398 ) Web feeds served as text/html won't load properly ( bug 381357 ) After installing some add-ons, the "Restart" button will not appear ( bug 414936 ) Some add-ons that depend on deprecated code may not install properly (see bug bug 406807 ) Privacy > History > Remember visited pages to "0" has no effect ( bug 366075 ) The DOM Inspector has been removed, and is now available as an add-on . Microsoft Windows A Windows Media Player (WMP) plugin is not provided with Windows Vista and some other versions of Windows. To view Windows Media content, you must install this plugin by following these instructions . After installing you may need to check for Windows Updates before the plugin will show content properly. If the highest security level is chosen in the Windows Internet Options, binary files will be deleted after they are downloaded (see bug bug 416683 ) Mac OS X The "More Information" button in the web site identity dialog does not launch the Page Info dialog (see bug 415704 ) Linux and Unix Users running Ubuntu 7.10 may need to update their certificate databases in order to submit crash reports (see bug 407748 for instructions) The mouse button assignments for Back and Forward have changed, users may need to reconfigure their pointing devices (see bug 420294 ) Troubleshooting Poorly designed or incompatible extensions can cause problems with your browser, including make it crash, slow down page display, etc. If you encounter strange problems relating to parts of the browser no longer working, the browser not starting, windows with strange or distorted appearance, degraded performance, etc, you may be suffering from Extension or Theme trouble. Restart the browser in Safe Mode. On Windows, start using the "Safe Mode" shortcut created in your Start menu or by running firefox.exe -safe-mode. On Linux, start with ./firefox -safe-mode and on Mac OS X, run: cd /Applications/Firefox.app/Contents/MacOS/ ./firefox-bin -safe-mode When started in Safe Mode all extensions are disabled and the Default theme is used. Disable the Extension/Theme that is causing trouble and then start normally. If you uninstall an extension that is installed with your user profile (i.e. you installed it from a Web page) and then wish to install it for all user profiles using the -install-global-extension command line flag, you must restart the browser once to cleanse the profile extensions datasource of traces of that extension before installing with the switch. If you do not do this you may end up with a jammed entry in the Extensions list and will be unable to install the extension globally. If you encounter strange problems relating to bookmarks, downloads, window placement, toolbars, history, or other settings, it is recommended that you try creating a new profile and attempting to reproduce the problem before filing bugs. Create a new profile by running Firefox with the -P command line argument, choose the "Manage Profiles" button and then choose "Create Profile...". Migrate your settings files (Bookmarks, Saved Passwords, etc) over one by one, checking each time to see if the problems resurface. If you do find a particular profile data file is causing a problem, file a bug and attach the file. Frequently Asked Questions What can I do to help? We need help from developers and the testing community to provide as much feedback as possible to make Firefox even better. Please read these notes and the bug filing instructions before reporting any bugs to Bugzilla . You can also give us your feedback through this feedback form . If you're interested in helping us test pre-release builds, you might want to join our beta test mailing list . Why haven't you responded to the mail I sent you? Use the forums . The Firefox team reads them regularly. We all get a lot of email, and your email may get lost. Where can I get extensions and themes (add-ons)? Extensions and Themes can be downloaded from Firefox Add-ons . Who makes Firefox 3 Beta 4? Lots of people. See Help->About Mozilla Firefox, Credits for a list of some of the people who have contributed to Firefox 3 Beta 4. Where's the Firefox 3 Beta 4 source code? A tarball of the Firefox 3 Beta 4 source code is available for download . The latest development code can be obtained by cvs . Firefox-specific source is in "mozilla/browser", "mozilla/toolkit", and "mozilla/chrome". Please follow the build instructions . Where is the mail client? Firefox 3 Beta 4 works with whatever mail client is the default on your system. However, we recommend Mozilla Thunderbird , our next-generation email client and the perfect complement to Firefox.

Hopefully all of the people who make add-ons will be caught up by the release date. I tried it about a month back and only a few of my add-ons worked. Didn't take but 5 minutes of use before I uninstalled it.

I agree, a lot of them are not working. I am trying to use it but I think I am going to uninstall it again. I need that right click malware search addon back

Cool, i'll be waiting until it's finished it's BETA testing stage before I download and use it