Mozilla on Tuesday released the first major interface refresh for Firefox since relaunching the browser in 2011, making more than 1,300 changes to the browser in an effort to win users away from Microsoft's Internet Explorer, Google's Chrome, and Apple's Safari browsers.

The massive overhaul comes at a time of challenge and opportunity for the company's leaders. Mozilla was riven with internal strife several weeks ago when company co-founder and longtime Chief Technology Officer Brendan Eich was elevated to chief executive and then resigned 11 days later, following a public outcry over his financial support for an anti-gay marriage law in California.

But the sweeping improvements in Firefox 29 for desktops also come a day after the US and UK governments cautioned users against using IE until Microsoft fixes a new security hole that could allow attackers to install malware on computers without users' permission. The malware could then be used to steal personal data, track online behavior, or gain control of the computer.

Firefox is currently the third most used browser after IE and Chrome, according to NetMarketShare.

Among the new features in Firefox for desktop PCs are a Firefox Account to simplify the cross-browser Sync feature, a customizable graphical menu, and rounded tabs that emphasize the tab you're in over the others.

"People are using the Web differently than they used to," said Johnathan Nightingale, Mozilla's vice president of Firefox, "and we need to give them a richer set of tools for customizing the way that they experience the Web."

The new interface

The visual changes take some cues from adjustments that Google has made to Chrome and Microsoft has made to Internet Explorer, such as the triple-line menu icon that now lives on the righthand side of the browser. Gone from Windows and Linux is the orange Firefox menu button.

Mozilla

Two smaller changes arrived early. People who use Firefox have already been exposed to the Download Manager button on the add-on bar, and the browser navigation Forward button disappears unless there's a page to move forward to.

But other improvements are more drastic. The menu button has jumped completely from the left to the right side of the browser, and introduces a touch-friendly, icon-based, customizable menu to Firefox fans.

"Most desktops are not touch enabled, but they're moving that way. You could say it's picking up design ideas from mobile, or you could just say that it's well designed," Nightingale said.

Nightingale doesn't expect everybody to like the new look. His solution? To call up one of the browser's best-loved features: customization.

"We've always been proud of our add-on experience, but the built-in customization tools were in need of love," he said. You can now drag-and-drop to customize the menu, just as you can with other browser interface elements such as the location bar or search box.

Another important interface change has been to ensure that tabs are readable. Tabs, Nightingale said, are a "critical detail."

"Talking about tabs is talking about how people do more than one thing at the same time on the Internet," he said.

Firefox has developed a reputation as a browser than can smoothly handle dozens of tabs, and so Nightingale said it was important for Mozilla to make sure that tabs remained legible even as more of them got crammed onto the tab bar.

"We decided not to shrink and shrink the tabs, which would theoretically allow you to have more of them on the screen. It makes more sense to have nice smooth animation and keep some content there to give your eye something to look for," he said.

The browser relies on your mouse scroll wheel or navigation arrows at either end of the tab bar for you to access overflow tabs.

Rethinking Sync

The new Firefox Sync steps back from the previous way users were asked to set up the feature, which allows you to synchronize tabs, bookmarks, add-ons, preferences, passwords, and browsing history across devices and operating systems. The old Sync required people to input a complicated, randomly-generated password, and it was buried in the settings menus.

Mozilla

The new model is based on the more familiar user-chosen username and password, and receives its own icon and account identifier in the new menu. Mozilla began making Firefox Accounts available to the public several months ago through its developer's build, Firefox Aurora. It's expected to support multifactor authentication, but doesn't at the time of launch.

"Five to 10 percent of the new [Firefox] Accounts on [Firefox] Beta are originating on Android," Nightingale said. Mozilla believes that the new Sync sign-up is helping the Android version of the browser finally take off, a complementary but important goal of the redesign.

"There are hopeful signals there that people are responding to the new sync," he said.

Mobile and the future

Firefox was introduced in 2004 and pitched as a faster, more secure, and more personable alternative to Internet Explorer. As the heir to Netscape, it won over users but was taken by surprise when Google Chrome launched in 2008 with an emphasis on minimalism and speed.

Firefox's customizable, developer-friendly alternative had drawn accolades when compared to Microsoft's bloated, buggy Internet Explorer, but Chrome forced Mozilla to rethink its approach. In 2011, Mozilla's update to Firefox 4 heralded enormous changes to the browser, including a new interface and a six-week update cycle borrowed from Google and the mobile world that brought smaller improvements more frequently. Previously, major-point updates came only once every two years.

Mozilla

Since then, updates to the browser have focused on introducing new features, advancing Web standards, and making the browser faster and more nimble with occasional interface tweaks.

Mobile has been a harder sell for Mozilla. The first attempt at Firefox for Android, which debuted in March 2011 alongside Firefox 4, was scuttled in June 2012 for a complete rebuild of the browser that addressed long-standing complaints about speed and performance. It's hard to say whether that was a crucial blow to Firefox for Android, given the myriad of upgrades that Android itself went through during that time, but it certainly didn't help mobile Firefox adoption to have a subpar entry on the board.

According to NetMarketShare, desktop Firefox's market usage percentage has slowly drifted south over the past year, from more than 20 percent in May 2013 to 17.26 percent in March 2014. That's not necessarily terrible news, as the number of the people using the Internet continues to increase.

But on Android, Firefox can't even pick up 0.01 percent of the users, says NetMarketShare.

Still, Nightingale insists that Firefox is trending towards greater adoption on Android.

"We've been seeing a lot of response to [Firefox for] Android," he said, noting that the browser has passed 50 million downloads, with 20 million active users and a 4.5 star rating in Google Play.

"The thing we need to do is make stronger ties between desktop and mobile," he said, but also pointed to Mozilla's successes in other browser areas.

3D games, he noted, are running at close to native code speed in the browser thanks to Mozilla technology such as Emscripten and ASM.js, and the long-awaited Unreal Engine for game-building running directly in Firefox.

It's the kind of real-world benchmark that users can go out and test for themselves, something that the microbenchmarks calculating the milliseconds of JavaScript rendering times can't easily do.

Release notes for Firefox 29 for desktops and Firefox 29 for Android are available.

Firefox 29 positions Mozilla's pieces on the board for a strong future. But the question remains: Will erstwhile fans will return to play the game?