Released: November 19, 2007

Firefox 3 Beta 1 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.

Much of the work leading up to this first beta has been around developing the infrastructure to support a bunch of exciting new features. With this first beta, you'll get a taste of what's coming in Firefox 3, but there's still more to come, and much of what you'll see is still a bit rough around the edges.

Please see below for an extensive list of features and enhancements found in Firefox 3 Beta 1, 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.

What's New in Firefox 3 Beta 1
Firefox 3 Beta 1 is based on the new Gecko 1.9 Web rendering platform, which has been under development for the past 27 months and includes nearly 2 million lines of code changes, fixing more than 11,000 issues. Gecko 1.9 includes some major re-architecting for performance, stability, 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 under the hood to offer website and Firefox add-on developers.

More Security
One-click site info: Click the site favicon in the location bar to see who owns the site. Identity verification is prominently displayed and easier to understand. In later versions, Extended Validation SSL certificate information will be displayed.
Malware Protection: malware protection warns users when they arrive at sites which are known to install viruses, spyware, trojans or other malware. You can test it here (note: our blacklist of malware sites is not yet activated).
New Web Forgery Protection page: the content of pages suspected as web forgeries is no longer shown. You can test it here.
New SSL error pages: clearer and stricter error pages are used when Firefox encounters an invalid SSL certificate.
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.
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.
New Download Manager: the revised download manager makes it much easier to locate downloaded files.
Resumable downloading: users can now resume downloads after restarting the browser or resetting your network connection.
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.
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.
Integration with Vista: Firefox's menus now display using Vista's native theme.
Integration with the Mac: Firefox now uses the OS X spellchecker and supports Growl for notifications of completed downloads and available updates.
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.
Location bar & auto-complete: type the title or tag of a page in the location bar to quickly find the site you were looking for in your history; favicons, bookmark, and tag indicators help you see where results are coming from.
Smart Places Folder: quickly access your recently bookmarked and tagged pages, as well as your more frequently visited pages with the new smart places folder on your bookmark toolbar.
Bookmarks and History Organizer: advanced search of your history and bookmarks 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).
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.
Native Web page forms: HTML forms on Web pages now have a native look and feel on Mac OS X and Linux (Gnome) desktops.
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
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.
Speed: Major architectural changes (such as the move to Cairo and a rewrite to how reflowing a page layout works) put foundations in place for major performance tuning which have resulted in speed increases in Beta 1, and will show further gains in future Beta releases.
Memory usage: Over 300 individual memory leaks have been plugged, and a new XPCOM cycle collector completely eliminates many more. Developers are continuing to work on optimizing memory use (by releasing cached objects more quickly) and reducing fragmentation.
A more complete, yet "unofficial" list of Firefox 3 changes with their bug numbers is available at the Burning Edge website.

Downloading and Installing
System Requirements
Before installing, make sure your computer meets the system requirements.

Downloading Firefox 3 Beta 1
Mozilla provides Firefox 3 Beta 1 for Windows, Linux, and Mac OS X in a variety of languages. You can get the latest version of Firefox 3 Beta 1 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 1
Please note that installing Firefox 3 Beta 1 will overwrite your existing installation of Firefox. 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 1
You can remove Firefox 3 Beta 1 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 1 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: