Firefox 3 Beta4與上一個版本 Beta 3相比，在下載檔案管理員、優越的網址列、整頁縮放等功能方面改善幅度很大，而且瀏覽效率是整個提升上來，而還在測試中的beta 5 pre速度還比beta 4快。
代 號為Gran Paradiso 的Firefox 3最重要的功能就是整合性的瀏覽歷史、書籤功能Places，也就是Bookmarks on Places。另外，更新的瀏覽器引擎Gecko有更好的效能表現。另外還有續傳下載檔案管理員、整頁縮放、遠端資料夾功能、支援OpenID與微格式 (microformats)等等，microformats本站也有支援，可以看到簡單的連絡人資訊。
有興趣的用戶可以下載不同跨平台與語言版本的Firefox 3 Beta 4測試。
[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!] 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.