One of the most requested features: downloads can be paused and resumed across sessions, limited only by the server capabilities. Also, on Windows, downloaded files are automatically passed to the installed anti-virus if present and Windows Vista parental controls are honored.
As seen in previous betas, the Download Manager has received a serious face lift as an easier to track download list with search capabilities. Beta 4 introduces the ability to search the file size and download date in addition to the file name.
A status bar notification provides summarized status of current downloads. You can click it to open the Download Manager.
The Add-ons Manager has been integrated with Mozilla Add-ons, Mozilla’s official extensions and themes repository, providing recommendations, search, rating and add-ons install without leaving Firefox.
And a new Plugins page (identified with a neat Lego brick icon) allows easy plugin enabling and disabling, making the Add-ons Manager a powerful control panel for Firefox enhancements.
When installing, updating, disabling or enabling back an add-on, an information bar is displayed to remind a restart is needed for changes to apply, and a restart button.
Plus, just installed themes are automatically selected so Firefox uses it after the next restart.
Among other minor tweaks: FTP and gopher listings get a better styled and functional page where the list can be sorted by name, size and date by clicking the appropriate header, and a warning is displayed when accessing advanced preferences (about:config).
SecurityIn the security front, Firefox will check visited sites with a list of known malware sites -provided by stopbadware.org and served by Google- to prevent spyware, rootkits, viruses, dialers and other kinds of malware from even being offered to you.
A rewritten password manager now unobtrusively prompts to store an entered password in the information bar and after trying a logon so you know if it is the correct one or not and avoid cluttering autocomplete lists.
Identifying authentic sites and avoiding fake ones is now easier with the addition of the site button which provides details about the identity of the current web site. While the largest part of the web has no verified identity, financial institutions and similar usually do and it makes the site button in the location bar to change color and size so you can know with a glimpse.
As great as add-ons are they are also a liability and have proved they can become an attack vector. Firefox 3 requires add-ons updates to happen over an encrypted connection (to block malicious sites purporting the update site) or the add-on developer to sign it with a digital signature so updates can be verified to be from the same source. This will prevent middle-man attacks where bad guys could fake an update site address to serve malicious software.
Invalid or expired web site certificates now get an unfriendly treatment that requires adding the site to a white list. This should encourage web site owners to keep their certificates up to date so they can effectively ensure their visitors a more secure experience.
Under the hood
The list of changes for Gecko is not short either and benefit not only Firefox but all “powered by Mozilla” products including Thunderbird, Flock, SeaMonkey, Joost, Miro, Songbird and more.
Since Alpha 1, Firefox 3 passes the Acid2 test, a popular test of a browser styling standard compatibility. As of this Beta 4, Firefox 3 scores 67/100 in the Acid3 test. Not that bad for a test just released a few weeks ago.
Firefox support color profiles embedded on pictures and images to better replicate the original environment conditions as light and focus, thanks to new color management.
Discontinuous selections of text and images are now possible for better control of what you copy or print from a web page.
A biggie: page zoom magnifies the complete page and not only text. This is a much requested feature and a must for Mozilla plans for a Mobile Firefox. Beta 4 adds an option to choose whether you want to zoom the whole pager just text.
Web developers can mark certain web page components such as images and scripts to be available while offline. In practice you could be able to compose emails or write documents though a web service while disconnected from the Internet.
Support for editable content, so a user can change portions of a web page marked by the author.
The MySpell spell-checking engine has been replaced with Hunspell which does a better job handling complex languages including Asian, Hungarian, Basque, etc.
For Gecko 1.9, Mozilla switched to open source Cairo rendering engine for better rendering performance. The change also enables easy PDF printing capabilities but it is only possible through an extension right now though.
More beautiful animated images are possible with animated PNGs (APNG): a full 16 million color palette and partial transparency will hopefully sweep GIF images in the future. While APNG was rejected as a standard PNG extension last year, Opera has announced it will support the format in future versions.
Proprietary TalkBack, the tool for reporting crashes to Mozilla included with Firefox and Thunderbird, has been replaced with open source Breakpad (formerly Airbag).
Socorro, is a server crash reporting tool that will help developers track the most recurring crashes and identify stability and performance bugs. Users can see their submitted crashes entering about:crashes in the location bar.