Mozilla Posts First Pre-Release Code For Firefox 4

Firefox 4 Pre-Release, Codename Minefield

The first pre-release version of Firefox 4 has shown up in Mozilla's nightly builds page for developers.

The first actual beta meant for public testing beyond developers is expected in the next couple of weeks. Dubbed "firefox-4.0b2pre" the installer offers the first peak at what the open-source Web browser, due out by the end of 2010, might look like. It also adds support for Google's WebM open-sourced video format.

The browser prototype, whimsically and ominously called "Minefield," sports a redesigned user interface that seems to borrow from Chrome and Opera, with tabs up top and no menu. You have the options to turn the menu bar back on and to move the tabs back down. The menu is replaced by an "App button" at the top left of the window border, which drops down options when pressed. Firefox designer Stephen Horlander said that the inspiration for this came from Windows 7 native apps such as Paint.

I still see no action for choices on new tab pages: All other browsers offer some choice of history and favorites when you open a blank new tab, but Firefox's new tabs are still just that—blank.

Inside, the new browser features a new JavaScript engine called JagerMonkey, which takes advantage of Apple's open-source Nitro JavaScript JIT (just in time compiler). Like Internet Explorer 9, Firefox 4 has as a design goal to use graphics hardware acceleration wherever possible, but much of this work hasn't made it into the pre-release build yet. In a quick test on my 3.16 dual-core with 4GB RAM, the pre-release posted a SunSpider benchmark time of 675ms, a 23 percent improvement over Firefox 3.6, but still trailed Chrome, Opera, Safari, and Internet Explorer 9 Platform Preview.

One of Firefox's hallmarks has long been its extensive Extensions capability, and in version 4 it will see an overhaul, with the new JetPack SDK. This will make add-ons easier for a large audience of Web programmers to build using HTML, JavaScript, and CSS. It will also spare users from having to restart the browser when they install new add-ons. But the add-on page in the pre-release of version 4 beta still had a disclaimer saying "This page isn't done; lots more improvements coming soon!"

The pre-beta candidate was surprisingly stable in my testing for such early code, though I did run into a glitch at one point while trying to access browsing history. Look for a full hands-on evaluation here when the actual beta is released in a couple of weeks. For the intrepid testers of early code builds, you can navigate to the Firefox Nightly Builds page.

About Our Expert

Michael Muchmore

Contributor

My Experience

I've been testing PC and mobile software for more than 20 years, focusing on photo and video editing, operating systems, and web browsers. Prior to my current role, I covered software and apps for ExtremeTech and headed up PCMag’s enterprise software team. I’ve attended trade shows for Microsoft, Google, and Apple and written about all of them and their products.

I still get a kick out of seeing what's new in video and photo editing software, and how operating systems change over time. I was privileged to byline the cover story of the last print issue of PC Magazine, the Windows 7 review, and I’ve witnessed every Microsoft misstep and win, up to the latest Windows 11.

I’m an avid bird photographer and traveler—I’ve been to 40 countries, many with great birds! Because I’m also a classical music fan and former performer, I’ve reviewed streaming services that emphasize classical music.

Technology I Use

For everyday work, I use a good-old Dell tower with 16GB of RAM, a 12th-gen Intel Core i7 processor, and an Nvidia RTX 3060 Ti GPU that runs on Windows 11. I pair it with a 4K Lenovo ThinkVision P27u-10 monitor and a Logitech MX Vertical mouse. For offsite work, I use a 2024 Microsoft Surface Laptop with a Qualcomm Snapdragon X Elite processor. Camera-wise, I moved to mirrorless from a Canon EOS 80D with a Canon 70-300mm IS USM lens. I now have a Canon EOS R7 with a 100-400mm lens, but I miss my DSLR for several reasons.

In order of usage, the software I turn to most frequently is the Edge web browser, Slack, Adobe Creative Cloud, Microsoft 365, Firefox, Brave, and WhatsApp. I use the Windows Phone link app to see everything on my Samsung Galaxy S21 Ultra phone, which has excellent telephoto capability.

For fitness monitoring, I have a Fitbit Charge 6 and use an Anker Smart Scale P1. I’m also a streaming fan, so I subscribe to both Amazon Music Unlimited (especially for its Dolby Atmos content) and Qobuz (for its high-res sound quality and classical catalog). I recently added a Vizio 5.1 Soundbar SE, which sounds surprisingly good given its low price. To holler commands instead of using a remote control, I have the Amazon Fire TV Cube in the living room, which lets me verbally tell the TV what I want to watch. It hooks up to an LG B4 OLED TV. I have a Sonos One speaker in my kitchen that also ties in with Alexa, as does the Echo Dot 2 With Clock in my bedroom. For serious listening, I have B&W 601 speakers plugged into a Conrad-Johnson Sonographe amp and preamp, with a Cambridge Audio AXN10 streamer as source. For reading, I also have a Nook GlowLight 3.

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