Whenever Firefox Aurora gets a bump, I write about the new features and changes of the release to give beta and stable users a heads up what they can expect when their channel moves to that version.

Firefox 9 introduces type inference in the browser which improves the browser’s JavaScript performance in the two digit range. The Mozilla developer who worked on introducing type inference noticed performance increases of up to 44%, independent testers results between 20% and 30%.

The few remaining features and changes are not that spectacular. Mozilla notes that the browser is now supporting the new application toolbar and icon styles of Mac OS X 10.7 Lion as well as multi-monitor support and two-finger swipe navigation gestures on the operating system.

Web developers can make use of JavaScript DNT Detection which detects if a user has opted out of behavioral tracking. The only other feature is supported for chunked XHR requests which can be utilized to display “data as it arrives instead of waiting for an entire download to complete”.

Firefox for Android users who can download a version of Firefox 9 for their system as well will notice a lot of changes. The browser now has a new look and feel to it. This includes a new awesome bar design with quicker access both to bookmarks and history items but also to preferences, add-ons and downloads. Back and forward buttons have been added to the awesome bar for easier navigation.

Firefox for Android users will benefit from faster start-up times, especially on devices with slow file systems.

Type inference is without doubt the biggest new feature of Firefox 9. One could say that it is the only end user feature of the desktop version. Only Mac users benefit from additional support for the new Lion operating system.

If you are interested in Firefox 9 you can download it from the Future of Firefox website for desktop and mobile devices.

The new Opera 9.5 beta 2 is currently available for Windows Mobile and Symbian UIQ. A release for Symbian S60 phones is planned for 2009. The biggest new feature in this version is the mobile widgets support. Users should not confuse mobile widgets with widgets in desktop versions of Opera because they work and act different which is mainly caused by the limited screen space of mobile phones.

Widgets for Opera mobile are basically one click services that either open a function or website directly. Only a few widgets are currently available including a clock, Twitter or weather information.

Other additions are a new Zoom slider and some user interface and usability improvements in addition to many under-the-hood fixes in the browser core. It is a good time now to test the new Opera mobile browser if you have a mobile device running Windows Mobile or Symbian UIQ.

Since the distribution rate of Nokia N810 Internet Tablets is surely slim most users will experience the mobile version of Firefox on desktop PCs instead. The desktop PC release is aimed at users who want to test and expand the mobile client version of Firefox.

Users can download the first version of Mozilla Fennec M9 on the project website where versions for all supported devices and operating systems can be downloaded.

Features of Firefox Mobile alpha:

Easy navigation to Web content:

• Bookmarks, including tags
• Smart URL bar (“awesome bar”)
• Tabbed browsing with thumbnail images
• Integrated Web search – built into the URL bar
• Easy access to multiple search engines

Web content:

• Maximize content by auto-hiding controls and URL bar
• Zoom in and out

Security:

• Instant Web site ID (“Larry”)
• Password manager
• Popup blocker
• Clear private data

Devices services integration:

• Click on a phone number to initiate a call
• JavaScript API to get device location
• Popup blocker
• Clear private data

Also:

• Searchable download manager
• Preferences pane

Mozilla Fennec can be started after downloading and unpacking the release without installation which makes it a portable release.