Under the Hood
WebM and HD Video
As pioneers of HTML5 video standards, Firefox also supports the WebM format so you can watch open HD quality video.
Protecting Your Privacy
Firefox puts your privacy first, fixing flaws in some web standards that allow bad guys to snoop around and expose your browser history.
New JS values
Changes to the C++ representation of JavaScript values allow Firefox to execute heavy, numeric code more efficiently, resulting in cleaner graphics and a better browsing experience.
Multi-touch Support
Firefox now integrates multi-touch support for Windows 7, enabling you to interact with your browser in a whole new way.
3D on the Web
WebGL brings 3D graphics to Firefox, opening the door for developers to create vivid games and new kinds of visualizations and experiences for the Web.
Audio API
Firefox is changing the way media is integrated on the web: exposing the raw audio data housed within the <video> and <audio> elements in HTML5 makes it easy for developers to use JS to read and write audio data.
Retained layers
Experience super fast scrolling on complex web pages. Simply awesome.
XPCOM
Firefox starts up even faster thanks to XPCOM module improvements that pave the way to a better extensions framework.
Stylin’ Pages with CSS3
Support for new CSS3 features like Transitions and Transformations makes it easy to add elegant animations to Web pages. Learn more
Fabulous Fonts
Firefox 4’s OpenType font features gives designers and developers more control over a variety of font features—like kerning or ligatures—to create gorgeous websites.
Upgrading Forms
Firefox integrated Form features like list attributes and HTML5 validation provide the tools to make annoying form implementation development a thing of the past.
HTML5 Support
A new HTML5 parser and full support for web video, audio, drag & drop, and file handling means Firefox 4 is ready to run the best web apps of both today and tomorrow.
Web Console
With this experimental analysis tool for modern sites, Firefox allows you to peek under the hood of dynamic web pages.
JetPack SDK (Making Add-on Development Easier)
Add-ons can be installed without restarting the browser, and can be developed more easily using the new JetPack SDK and js-ctypes.
Full Hardware Acceleration
Experience super-fast graphics acceleration with Direct2D and Direct3D on Windows, XRender on Linux and OpenGL on Mac, now enabled by default, on all supported hardware.
SVG as Images
SVG files can now be used as images and backgrounds in Firefox, meaning that developers and designers can have stunning, performance-conscious websites with lighter, resolution-independent image files.
Compartments
Firefox can now better manage JavaScript objects with Compartments, offering improved cache utilization and garbage collection mechanisms for better security, memory management and overall performance.
Crash Protection
Firefox provides uninterrupted browsing for Windows, Linux, and now Mac when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins. If one of these commonly-used plugins crashes or freezes, it won’t affect the rest of Firefox. Instead, you can simply reload the page to restart the plugin and try again. Learn more about plugins.
HSTS
Sites can now keep attackers from intercepting sensitive data while accessing the site by telling Firefox to automatically establish secure connections to their servers (https).
