Mozilla’s Firefox web browser has undergone some major changes in recent years. Support for unsigned extensions is being phased out. Tabs have moved to the top of the screen and settings menus hide behind a button on the right side of the screen. Overall Firefox looks a lot more like Chrome than it used to.

Soon it’ll even be able to support Chrome add-ons and extensions. That’s kind of cool, right?

But Firefox will also phase out support for legacy plugins based on XUL… which is a bit less cool.

ff add

Mozilla has announced that it’s changing its approach to add-ons in several key ways.

The first is the introduction of a new API called WebExtensions which is mostly compatible with the tools developers use to create extensions for Chrome and Opera web browsers. This will make it possible for you to install existing Chrome extensions in a Firefox web browser. But just as importantly, it means developers will be able to create cross-platform extensions that will be able to run on different web browsers.

Second, as Mozilla moves to a multi-process version of Firefox (another feature that makes the browser act more like Chrome), developers will need to make sure that their plugins are compatible with the Electolysis multi-process system.

Next, as expected, Mozilla will require that most extensions be validated and signed… When Firefox 41 launches on September 21st, unsigned extensions will be turned off by default, but users will be able to disable signature enforcement. When Firefox 42 is released around 6 weeks later, there won’t be an option to run unsigned extensions… but you can get around this by installing nightly or developer edition versions of Firefox.

Finally, the Firefox team is phasing out support for XPCOM and XUL-based add-ons. Mozilla says this will make the browser more secure and more stable… and without making this change, the team would be unable to implement the Electrolysis mult-process architecture.

So within the next 18 months, Mozilla plans to kill off support for these legacy plugins while encouraging developers to re-write them using WebExtension API or the JetPack SDK. But Mozilla acknowledges that some existing plugins can’t be rewritten using those tools, because they rely on functionality that’s not included.

The goal is to add features to the WebExtension API in the next year and a half, but it’s possible that some existing plugins will never be able to make the transition since they rely on a “permissive” model that allowed for deep integration into the browser… and that’s exactly the sort of thing Mozilla is ruling out for future add-ons.

The developer of popular Firefox add-on DownThemAll, for example, says he’ll probably stop developing plugins if Mozilla eliminates support for XUL-based add-ons because the new tools don’t offer the same kind of flexibility as those that are being deprecated.


While Firefox continues to use a different web rendering engine that Google Chrome, it sounds like the browser won’t just look like Chrome in the future… it’ll act almost exactly like Google’s web browser thanks to support for multi-process architecture, support for Chrome-compatible add-ons, and a walled-garden approach that only allows users to install signed and validated plugins.

So I have to wonder, is there still much reason to use Mozilla’s web browser rather than Google’s?

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30 replies on “Firefox to gain support for Chrome add-ons… and lose support for legacy XUL plugins”

  1. Mozilla has not yet provided support for Native calls. My plugins make use of XPCOM and I need to make native calls to support my plugin. Can any of you suggest how I should support the plugin starting from the new Firefox 41 to the future release as well? As per my knowledge, they have a future plan to support the native messaging, but till then how …!!! Moreover do any of you have any information, by when can we get the native support from Firefox.

  2. I’m already running a clusterfuck of extentions just to have tabs on the bottom. Remember when Firefox was the fantastic, customizable browser we all lauded over? Now they’ll remove the option of running the things I use to get around the previous options they removed.

    God dammit.

    And Opera post version 12 is even worse. (As is Vivaldi). How did the browser market get worse instead of better the last few years?

    1. I still need my status bar, so there’s an extension for that. Plus the extensions that rely on it.

      The extension I use that is most in danger of Mozilla’s moves is Social Fixer. It injects JS and CSS into Facebook (good luck doing that with WebExtensions!) to make using that site a tolerable experience. (Sounds similar to what we’ve been doing with Firefox itself) Of course, it isn’t distributed via the walled garden, so I’ve had to conf 41b3 into submission. Once 42b drops, it’s end of the line. Time to switch to Pale Moon.

      At this rate, the only useful version of official Firefox will be the “developer edition”. Its kinda stupid that a special “developer” version even exists. We should be using the same distro as our users, plussed up with extensions to do the debugging. Oh wait, that’s what Firefox was before the Chrome-copying me-too crowd took over!

      As for the big O, I’m still using Opera 11.64 (long live Presto!), as the next version up removed IRC on Mac. If you’re gonna rip out a feature, at least spin it off into an extension. The day your users stop upgrading is the day your product starts to die.

  3. I don’t much care for this change. I have used both Firefox and Chrome and I can’t stand Chromes add ons, They are mostly spyware and adware like anything else Google puts out. unlike Firefox’s add ons and when one is found to have ether problem it is usually reported by users or removed by Mozilla. I have found around 75% of Chromes add ons are malware, and Google could care less. That’s why I will never use Chrome. And if Firefox follows through with this change I will quit using it, even though I have used it for years.

  4. Can they quit fucking around with this browser? Not joking. Update this, update that. Change this, change that. Then things I’ve enjoyed stop working or become a hassle to use. IMO this version is broken, but sure, change it even more. Open the doors for more bugs and instability. Gotta change, and have to change often. That’s their philosophy. Might move on in the near future.

  5. Bring back Netscape! I kid I kid. Seriously folks, just install Pale Moon and be happy. Been on it for years since FireFox went ape shit and fell of the rails. Free yourselves from their desperation and have control of your browser again. GUI looks like old FireFox and is customizable like old FireFox. Just do it!

    1. But the cable company’s calendar widget for paying the Internet bill doesn’t work in Pale Moon. I know because I stubbornly refuse to switch to anything else and I send them a damn check rather than deal with their programmatic stupidity.

  6. This is a very dangerous move from Mozilla. At least, they should have waited until webextension gets properly refined to allow the implementation more powerful FF plugins. Or, they should have provided their own extensions on top of the Chrome APIs in order to, at least, make the rewrite of the plugins possible.

    This way, they loose a very important differentiation point and probably anger a lot of FF plugin developers.

    I highly appriciate the privacy efforts of Firefox but I also know very well that FF is behind is several key metrics. Just an example: There is still no simple, easy, built-in way of dropping the complete cache for the site you are browsing (not the whole cache, only the resources cached for the current site).

    Even with the problems with FF, I will probably continue using it as my primary browser.

  7. “So I have to wonder, is there still much reason to use Mozilla’s web browser rather than Google’s?”

    Big reason: Google’s browser spies on you (Evil). Mozilla claims they don’t.

    1. Well, Google’s browser also claims he doesn’t spy on you. You should monitor your network traffic to see how much Firefox is spying on you.

  8. FF – So much more like Chrome now, EXCEPT for one thing – they (supposedly) do NOT spy on you. Less Evil is good… Now, if they can just stop the huge memory leaks and add even the most basic bookmark management functions (you can’t even sort/reorder bookmarks!)

  9. The signing thing isn’t going to effect most people I think. I do wonder about the legacy extensions though and this new news.
    There is still some room for differentiation even if they were to adopt the Blink engine – which isn’t the case yet.
    Downthemall is a great third party downloader. That’s a favorite I’ll miss if it goes away. Unfortunately for me I don’t even use the ‘core’ features that he ight be losing access to. I just use it to download and that would still probably be doable.

  10. So it is official. I must migrate all of our users off of Firefox within the next two months. Time to evaluate the alternate products built from the Moz base and see if any of them are planning on remaining sane.

    What exactly is their official reasoning for why someone would want to stick with a browser that has a stated intention of only being a cut rate clone of Chrome with a different app store? An app store that, almost by definition, will only contain a smaller set of apps. I can’t wait to see that ad copy. Use Firefox! It is a pale imitation of Chrome but our DRM chains are better because….. because we are the cool kids?

    1. Java doesn’t work in Chrome when the next release goes out because they’re throwing out NPAPI plugin support. Java is required by many (most?) online classes, so Chrome won’t work with those online-enabled classes anymore.

      1. So? Pay attention; Firefox just announced they are also removing NPAPI as part of this taillight chasing game. Anyway, people have had a couple of years notice that Java was deprecated on the web, everybody has been throwing warning dialogs for at least a year on Java applets so I really can’t work up much concern for some idiot education software vendors who can’t keep up. Java is deprecated to the point Oracle isn’t investing more than bug fixes in the plugin, Flash Player development is essentially over (is over on Linux where I sit) and Adobe is throwing in the towel on a plugin for Reader so there really aren’t any widely deployed NPAPI plugins still in development and soon won’t be any in use so they might as well remove it.

        Bigger picture though is why bother with the follower when you can just use the leader and get the same features this year instead of next.

        And Firefox is now officially committed to just that, of spending the next couple of years at least, deprecating and removing every feature they have that isn’t in Chrome and adding in support for every Chrome feature down to running the same apps… except of course 100% compatibility never happens in a taillight chase, just ask the Wine Project. (Wine can’t even run the majority of non-trivial Win95 programs yet.) And of course they want to keep their own closed App Store so you will be looking at a pale subset of apps regardless; key word there being subset since they are forbidding keeping or adding any feature that would allow an app on Firefox that couldn’t also run on Chrome.

        Which is why the Moz codebase must be forked, why it will be forked, and why I will install one of those forks as our second browser. We currently use Firefox as the default with Chrome and Konquerer as backups. Unless a fork gets really good really fast it will probably be Chrome with some Seamonkeyish product and Konquerer as alternates.

  11. Ahh, smell the desperation of a dying franchise! Too bad they can’t be made to pay for all of the damage they’ve done to the web all of these years by warping the minds of a generation of web secretaries.

    1. Edge? Edge?

      Isn’t that the overpriced, jacked-up, recall-bait, Ford Pinto re-release I just saw advertised on this site?

  12. This is great. I stick with Chrome for the extensions. I haven’t used Firefox in years, but this could convince to switch back, provided that the extensions I use regularly run smoothly and without issues on Firefox.

    1. Are you serious? Mozilla’s extensions are one step above those on Chrome. On Firefox you don’t have ad flickering like you do on Chrome. You also have powerful extensions that are powerful in the first place thanks to increased access to the browser. Chrome’s extensions don’t come even close.

      1. Agreed. Chrome extensions aren’t even close to what Firefox has to offer. Even without extensions I really like the ability to rearrange the navigation buttons to anywhere I like (I’ve always preferred them to be on the right instead of the default left, because that’s where I often move my cursor to). I can’t do that in Chrome, which is a shame.

      2. Ad flickering? I ditched Firefox around 6 years ago because the memory usage was getting ridiculous. It was slow, even on a newer desktop computer. Of course, Chrome is far worse now, has been for a while. I open up Gmail in a tab, and check the usage, and sure enough, that tab alone is consuming 400mb of ram. Of course, that might be the fault of Gmail more so than Chrome. I wonder if Firefox has improved, especially for Linux. As long as Firefox uses less resources and is faster than Chrome (particularly on this old laptop), and it offer some of the extensions I use on a daily basis (or similar alternatives), I’m game.

        1. I ditched FF because their updating became unreliable on my machine–I’d have to manually install new updates.

        2. Yessssss. Firefox for Android leaks memory so bad. Nothing to do with add-ons.s. However, FF on the desktop is a stellar performer for me.

        3. Only a woman are capable to make a comment about technology so retarded.

        4. Firefox six years ago is not Firefox today. Chrome starts an entire new instance of the browser process for every individual tab you open. It is THE biggest memory hog in existence on any common desktop or laptop computer, bar none. It is also slow as dirt compared to Firefox, particularly when used over time and after piling on a lot of browser history. Chrome brought a lot of great ideas to the table in its youth; somewhere along the way, those ideas turned into disasters.

    2. Hope you never need Java…Chrome won’t support it at all in the next release, and Chrome is the biggest memory hog I’ve ever seen.

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