For all users who likes to be with the cutting edge Firefox has provided the Firefox 4 beta. It is a great experiences to be with the cutting edge but always wear your seat belts and helmets because this is a beta version.
UI(User Interface) changes in new vertion
whole new Firefox button
This works like the “Start” button in windows, everything stats here (All in one place).What we can see here is menu bar is missing that is a another change in new version. (If you want it back just press alt or you can go to Firefox button and enable it permanently)
New top tab model
As I said previously, Firefox need your feed back so when you feel happy or sad about some feature let them know about it. Give your support to free and open source software.
New features in Firefox 4 beta
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.
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).
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.
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
Firefox now integrates multi-touch support for Windows 7, enabling you to interact with your browser in a whole new way.
Experience super fast scrolling on complex web pages. Simply awesome.
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
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.
Firefox integrated Form features like list attributes and HTML5 validation provide the tools to make annoying form implementation development a thing of the past.
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.