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Note: This review addresses v4.0 of the software.

Much has changed since the Firefox 3.0 browser launched in June 2008. Google Chrome burst onto the scene, and has undergone frequent updates. Microsoft released IE8 and IE9. Safari advanced from version 3 to version 5. While Mozilla made some performance improvements and bolstered the feature set, Firefox started to feel like it was falling behind the curve. Firefox 4 makes Firefox competitive again, with its updated interface and better performance. The Mozilla designers did a good job simplifying the browser while maintaining the flexibility that Firefox is known for.

By default, Firefox 4 shows the address bar, a search field, the typical back/forward/reload/home buttons, the tab bar, and an orange "Firefox" button in the upper-left corner. Clicking the orange Firefox button brings up a single menu that contains most--if not all--of the menu items you're accustomed to using in older Firefox versions. If you're a Firefox power user--or just prefer the old menu bar--you can bring back the classic menu bar by clicking the Firefox button, mousing over "Options," then selecting "Menu Bar" from the drop-down.

One Chrome-inspired feature in Firefox 4 is the ability to "pin" Web apps to the tab bar. Open any Web app or Web page in a new tab, right-click the tab, then select "Pin as App Tab." This adds a tab showing only that page's icon to the far left edge of the tab bar. When you close then re-open Firefox, the pinned tabs will remain. Whenever something in your pinned Web app updates--say, you get a new message in your Gmail inbox--the pinned tab turns blue to notify you.

Like IE9, Firefox 4 includes a feature to prevent sites from tracking what you do online. This is a welcome addition, but it's flawed. When you enable tracking protection in FF4, it uses what are called HTTP headers to tell the site that you don't want to be tracked. The problem is that Websites don't have to honor this request, which renders the tracking protection feature useless. Mozilla is working to make this feature an industry standard, so I hope things will improve in time.

Firefox 4 also sports a number of new features designed to improve page loading and rendering performance. Firefox 4 can take better advantage of your graphics card than Firefox 3.x could; using it to play videos, for example. FF4 also includes an updated JavaScript engine.

We haven't done in-depth speed testing of Firefox 4, but we did test its JavaScript performance using the SunSpider 0.91 benchmark. Firefox 4 completes the test in 363 ms on average, making it competitive with other current browsers. In my testing, all browsers averaged between 329 and 439 ms. Your mileage may vary based on your hardware, OS, and other factors, but there's no denying the fact that Firefox 4 is much faster at handling JavaScript than Firefox 3.6.

New in Firefox 4 is Firefox Sync, which lets you sync your bookmarks, browsing history, passwords, and other data with your other computers running Firefox. (This was previously available via an extension called Mozilla Weave Sync).

Firefox 4 is a must-have upgrade if you're running Firefox 3.x. If you've switched from Firefox to Chrome, however, Firefox 4 may not lure you back, as many of the new features--at least on the user interface end--are clearly influenced by Chrome. But no matter what, it may be worth downloading and taking for a spin.

Note: This link takes you to the vendor's site, where you can download the latest version of the software.

--Nick Mediati

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At a Glance
  • This browser is faster, sleeker, and easier to use in its latest incarnation.


    • Thousands of add-ons make it a "Swiss Army knife"
    • Superb HTML 5 performance


    • Too many add-ons can slow down the browser
    • Slow page loads
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