Firefox 4 will be the biggest release in its history in terms of the amount of changes coming to the most widely used open-source software and the second most popular browser. A lot of these changes are a long time coming and Mozilla has received some flack in recent times for not being able to keep up with the pace of changes in performances and features already available in much lesser used browsers. Some even went as far as calling Firefox the new IE with its constant stability issues and lack of major updates.

Lets look at some of the exciting changes coming to Firefox 4, which is expected to be released by the end of this year. Some of these changes are already available on Minefield nightlies.

1) Major UI Redesign:

If you look at the new Firefox 4 UI you might confuse it with Chrome design, since the tabs are now on top. But to be precise the new Firefox design looks less like Chrome and more like Opera 10. Alas Opera never gets credit for design and feature ideas, which is likely where chrome found their design inspiration and Firefox 4 followed.

Firefox Minefield on top, Opera 10 at bottom.

Mozilla is moving cautiously with this new design choice and they started to promote the new tab on top choice. But rest assured, its not a question of if they will do it. The decision has been made already they are just promoting the idea to make sure that the majority are kosher with the idea. As far as the new menu bar is concerned, it may stay there by default but you will have a choice to go back to the old format.

Another design concept they took from Chrome is the Sticky Tab concept where you will be able to leave your most widely used website in the form of a permanent tab/button on one corner. You could do this with Firefox extensions, but now it will be a permanent feature with Firefox 4.

2) JägerMonkey JavaScript Engine:

Its amazing how fast things changes in such short time. In less than a year ago Firefox was proud of having one of the fastest JavaScript Engine out there and Opera, IE had one of the worst performing JavaScript engines. Fast forward now, Opera has the fastest JavaScript engine as far as stable releases are concerned and even IE9 preview is beating Firefox in JS performance but a long shot.

Firefox currently uses nanojit for its native code generator and will be moving to Webkits JSCore engine for Firefox 4. Which combined with Tracemonkeys powerful optimization should give them a better performance over their current engine. However it will be interesting to see how or if they will ever get faster than other webkit engine as far as JavaScript performance is concerned, since their implementation will be based on webkit.

3) New add-on manager:

Firefox 4 will be featuring a new add-on manager which will work on the background to update extensions instead of all the annoying pop-ups on every startup or every time there is an update available. You will also be able to search and install extensions from within the add-on manager. The UI itself looks a lot like the new Ubuntu Software Center.

4) TaskFox:

Perhaps one of my favorite feature or at least the one that I am most looking forward to, is TaskFox. Which is an implementation of the power of Ubiquity within the Firefox browser. If you ever used Ubiquity you will understand how exciting this is. The final implementation may not be as powerful as ubiquity but you can check out the demo video and see what it actually does or try it yourself (very limited demo).

5) More Standard Compliant:

Firefox has always been in the cutting edge when it comes to being standard compliant. With Firefox 4 they are pushing the envelope farther by supporting some of the CSS3 and html5 standards missing on Firefox 3.5. Some of those major supports coming on Firefox 4 are:

– CSS Transition

– CSS touch properties

– Forms in HTML5

– HTML5 Sections

– Support for WebM video

– WebGL

There are literally dozens of new standards coming up on Firefox 4, if you are a developer/designer you should definitely check out the whole list. However, it is important to understand that some of these standards are not necessarily de-facto standards, but standards that are likely to be accepted soon.

Final Thoughts:

I have always been a big supporter of Firefox and converted many friends and family to move to FF when IE development was stagnated. However in recent times FF was infected with the same bug that destroyed IE. The bug of slow innovation. Firefox has been slower and more crash prone in recent times and thats why I moved to Chrome which is innovating in extreme pace.

However Firefox 4 new features and UI looks like a great reason to go back to using it as my default browser. Here, I just mentioned some of the main features that will end up in the final version, there are literally 100s of new features that I didnt mention. Including one big one, Electrolysis, which is similar to tab per process model Chrome currently uses. However it is not clear if it will make in to the final Firefox 4 release.