Firefox 3.6 is here!

Firefox 3.6 has some cool consumer facing features like Personas and a better Plug-in Updater, but developers have a lot to be excited about too.  Developers will appreciate the increased stability, especially the work done to prevent crashes with third party software.  There are also enhancements like improved JavaScript performance and optimizations to speed up everyday Web tasks to make web applications snappier.  However, what developers will be most interested in are all the new features around CSS3 and HTML5 that bring the future of the Web to Firefox 3.6 today. 

This is an exciting release because we have built on the progress we made with Firefox 3.5 just a few months ago and have implemented even more cutting-edge features that will make the Web experience more engaging and interactive than ever before.

Today’s Firefox 3.6 release and the upcoming mobile release of Firefox for Maemo are both based on Gecko 1.9.2 and bring a number of big features including:

For a more in-depth look at all the changes that developers will want to know about please check out Firefox 3.6 for Developers on MDC. And if you haven’t already, go get Firefox 3.6 now!

About Paul Rouget

Paul is a Firefox developer.

More articles by Paul Rouget…

About Jay Patel

I strive to make the web better by making sure those that develop and drive it are happy campers.

More articles by Jay Patel…


  1. itroot

    woohooo Congrats!!!

    January 21st, 2010 at 10:46

  2. […] the 3.6 release announcement for details about what is new with this […]

    January 21st, 2010 at 11:00

  3. Royi

    This is a great release.
    The File API is the most important along with the Theora update.

    Hopefully the next version will catch up with Google Chrome’s speed (JS and Rendering by applying Direct 2D) and everything will be perfect.

    January 21st, 2010 at 11:02

  4. […] […]

    January 21st, 2010 at 15:11

  5. […] Mozilla Hacks – Firefox 3.6 is here! […]

    January 22nd, 2010 at 09:04

  6. […] 3.6/OpenOffice 3.2 rc 22 01 2010 E’ stato da poco rilasciato Firefox 3.6, le novità sono moltissime, tra quelle (a mio parere) più interessanti: il supporto ai font WOFF […]

    January 22nd, 2010 at 09:40

  7. Subrato Paul

    I am having problem similar to 3.5, that is repeated crashes. Is it because of Alexa add-on?

    January 22nd, 2010 at 22:26

  8. Elving

    If everyone in the world would just use firefox… Its cool having a browser supporting HTML5 and CSS3 but whats the point of doing something with it if every other browser fails on supporting this :(

    January 23rd, 2010 at 21:44

    1. Norio

      Opera has had working support of HTML5 and CSS3 since before Firefox. In fact, Opera pioneered the use of tabbed browsing and many other features used by Firefox and IE. IMHO, Firefox is bloatware.

      January 26th, 2010 at 10:52

  9. Subrato Paul

    It has become very difficult to run twitter on Firefox. Scripts like ajax/googleapis slowing down, firefox not responding and then crashing. I am now using chrome for twitter. But firefox is my favourite and default browser.

    January 24th, 2010 at 00:55

  10. […] Firefox 3.6 is here! – новата версия е тук. Като потребител това което ми харесва е че се усеща колко по-бърза. Също така все повече почва да свиквам с това че като дадеш “open in new tab”  табулацията се отваря до сегашния ти там. Като разработчик няма как да не се зарадвам на CSS3 градиентите, Drag and Drop и File API -то. […]

    January 24th, 2010 at 04:07

  11. Richard

    There’s a serious lag in the plugin updater – a week after Adobe had released Flash 10.42, it was still telling me that 10.32 was the latest version!

    The fundamental change to the position of newly opened tabs is annoying, and there doesn’t seem to be an option to switch back to the old behaviour.

    And what happened to the Windows 7 integration? It disappeared late last year, and there doesn’t seem to be any plan to bring it back. Obviously making your browser look like fluffy kittens is more important than making it integrate with the native operating system.

    January 25th, 2010 at 06:48

  12. Sam

    I like the introduced -moz-background-size most, can now use nice glorious backgrounds without size issues, yay!

    January 25th, 2010 at 18:40

  13. mike

    3.6 keeps crashing on me. Any ideas.

    Running a few persona’s

    Speed Dial

    January 25th, 2010 at 22:37

  14. Franchise Guy

    3.6 keeps crashing on me too… I can’t get past startup. >:(

    January 26th, 2010 at 15:33

  15. Peter

    3.6 keeps crashing on me too. Make me mad

    January 27th, 2010 at 08:57

  16. herry

    3.6 crashes timely on my machine every 15 minutes or so.
    Actually I was on 3.5.7 and it crashes like crazy so I upgraded to 3.6 which didn’t seem to fix it.

    I don’t know whether this upgrade worth congratulated for.

    January 27th, 2010 at 17:55

  17. Peter

    This link can solve the problem.
    FYI: removing or Updating YSlow to 2.0.6 fixed the crashing for me too.

    January 28th, 2010 at 06:44

  18. Kavih

    Please, can someone help me get the stable version of XulRunner 1.9.2? Sure FF3.6 was release with XulRunner 1.9.2 installed with it, but I’m not about to extract XulRunner from it. I’ve checked the following site:

    but all that is released is the RC1 or some 1.9.2pre… file here:

    which doesn’t reassure me that it is a stable build.

    Thank you very much if you can point me in the right direction.

    February 3rd, 2010 at 00:00

  19. Bob Waters

    One bug: like Google Chrome, and unlike all other builds of both Firefox and IE, when you “drag and drop” with Firefox 3.6, the “drop” fails. I’m thinking specifically of the layout section on Blogger. I have to use IE for this purpose. I hope this gets fixed soon.

    February 15th, 2010 at 21:55

  20. Rob


    I have been using FireFox 3.6 for 10 days with several plug ins and add ons. On my system all is OK. No crashes and it is faster than 3.5.

    I am using fireshot, scrap book, java console, WOT, ie view, microsoft net frame work., AVG safe search


    March 1st, 2010 at 06:39

  21. John Jackson

    Firefox has a very serious problem. It will not work inWindows 7 64 bit mode. I have had to go back to Internet Explorer. When will you get it fixed?????

    March 4th, 2010 at 08:20

  22. bafflez

    Flash stopped working the second I upgraded to v3.6 of mozilla. Every attempt to install flash results in a failure. I go to any video link in flash now on facebook and it says “Flash Player upgrade required. You must download and install the latest version of the Adobe Flash Player to view this content.”

    I’ve downloaded and installed it on the order of 5 times now. The flash install page shows it as working, and when I go to any other website, poof, no video, “you must install the latest version of Flash”.

    There’s not been much about this on google, nor here.


    March 12th, 2010 at 15:24

    1. Alex Smith

      Same problem here. I cannot get Flash to work.

      Any ideas anyone?

      March 16th, 2010 at 00:17

  23. haareez

    I got a strange problem on Firefox version 3.6, some yahoo mail account of my friend crash but mine did not have a problem with using the same computer, very frustrating problem, and I do not know why? {-(

    March 15th, 2010 at 09:38

  24. mcp

    3.6 broke functionality in Flash Player. Double clicking does not working in a Flex Application. I re-installed 3.5.8 and it all works again. I am running on a Mac.

    March 15th, 2010 at 09:39

  25. James

    Well after using Firefox for years, for the first time I really feel like dumping it for good.

    Constant crashing using Windows 7 (64bit),lagging/ crashing in XP??

    Add-on are what made Firefox and now they’re getting the blame for all the crashes.

    I hate to say it…… but IE8 is faster and more stable.

    sort it out M!!

    March 19th, 2010 at 11:52

  26. Morais

    FF 3.6 is HORRIBLE and INSTABLE, crashing every time (random) with out activate/come up the crash reporter… :-(

    I’m using a HP notebook, with Intel Core 2 Duo, 2GB RAM and Windows Vista Business SP2 – PORTUGUESE…

    I will revert/return to previous version… FF 3.5.7 to attempt solve crashs…

    March 19th, 2010 at 14:11

  27. bafflez

    What a surprise. They broke flash functionality and it’s been 2 months with no update? Bah!

    March 20th, 2010 at 13:28

  28. Carla

    I installed Firefox 3.6 a couple of days ago. Yesterday, I tried to get on and had nothing but problems. About the only site I can actually go to is Mozilla, and that hasn’t been helpful. Internet Explorer won’t do any more than Firefox. I tried uninstalling 3.6 and going back to an earlier version, but that didn’t help, either. My McAfee suite says I’m not protected, and I can’t do anything about that, ’cause I can’t go to websites. At this point, I’m frustrated and angry. I hate Firefox! Hmmmm…saying it doesn’t make me feel better. Is there a relatively simple fix, or will I have to pay an expert?

    March 21st, 2010 at 14:55

    1. sky

      I had same crash problems with newest 3.6 update..I restored my system to when it worked properly ..before that stupid bugged out it works FINE like it was

      March 3rd, 2011 at 10:25

  29. MLNplayer

    I too am having Flash issues. on sites like
    it is impossible to scroll the page from within the area of the game.. NOT a good result!

    March 22nd, 2010 at 01:14

  30. Sandra

    I don’t understand why but for the past couple days, Mozilla Firefox 3.6 has been crashing so many times it is getting very annoying. For some reason, every single time I log on to my university’s webct, java or something says it wants to block something that could potentially harm my computer. Then when I click on my classes and such, Mozilla crashes soon after. How can I fix this? It didn’t start to do this until after I installed the newest version of java.

    April 20th, 2010 at 07:48

    1. sky

      Its not new version of java.. It mozzilla update on 3.6 one day ago. Restore your system to before that sucky update..Works fine now :))))

      March 3rd, 2011 at 10:28

  31. Peter

    Flash plugin has been crashing after updateing to 3.6.4

    April 30th, 2010 at 13:14

  32. Shel

    My flash players crash at least 30 times a day using firefox 3.6.4.
    I’m now seriously considering using another browser and giving up on firefox.

    June 9th, 2010 at 09:04

  33. PRM

    I upgraded to the supposedly final version of FF 3.6.4 and none of my flash files even start playing. Works fine on every other browser: IE6,7,8 various Safari versions and Chrome.

    June 25th, 2010 at 11:17

  34. Alex

    Having the same problem!!! Upgraded to 3.6 a cople of days ago and it’s been chaotic!!! I can’t play anything from even youtube!!! I really like FF. It’s a shame I’m having to go back to IE!!! C’mon Mozilla get your act together!!!

    July 6th, 2010 at 12:17

  35. barry

    i did a recovery 3 times on my computer . i been trying to down load java an plugins so i can play on . i run me on my computer befor i did the recovery i could play on pogo. but now i have to have flash player 9 but it will not down load on my computer..i had internet explorer an i just got rid of it .every time i went on there i would use google .an i would put in a site to go to i would get this error on page an nothing would down load . so i would try every thing they told me to try an still nothing. i tried to down load avast an i could not down load i install norton antivirus . got it instaled but it will not let me scan the computer it has a red dot with a x on it. so can some one help me please.

    July 7th, 2010 at 20:02

  36. Charles Kolsrud

    So – is anyone at Mozilla reading this Blog? Don’t they get it? Every new version of FireFox since 2.0 has been buggier, slower and just plain irritating. I still love it, especially compared to IE, and I understand that software engineers, like any kind of engineers, are fuzzy on the concepts of end-users and operational efficiency BUT where are the guys at Mozilla who launched the early, great versions of this browser? Did Microsoft assassinate them or somehow infiltrate Mozilla? And how do you get back to 2.0? Every time I try, I wake up the next morning to find that 3.6 has re-installed itself through “updates” from Mozilla.

    My cripes: slow as hell, constantly have to refresh to get it to load properly,
    it can’t load more than a single page at a time (if you try you get the “can’t find” screen), it can’t handle complex pages that are trying to load multiple files (many of them ads, which more and more sites are incorporating) and it freezes, sometimes forcing me to hit the back button, sometimes forcing me to exit the screen altogether.

    So will you guys at Mozilla please get back to designing FireFox for the end-user and forget about all that loopy crap your software engineers are coming up with.

    Simplicity, Simplicity, Simplicity!

    July 13th, 2010 at 02:19

  37. howard barnes

    I am still getting FF (not responding) and FF crashes. Using FF 3.6.6. I am hoping for a fix or some guidance

    July 16th, 2010 at 11:17

  38. keepertoad

    yum update to 3.6.4 on centos 5.5 32 bit broke flash and java. Have not been able to get either to work. At first I thought I was brain dead but now think this is a ff issue. Is anyone finding a solution to what is apparently a common problem?

    July 20th, 2010 at 04:45

  39. Simon

    I am running Firefox 3.6.7 and I too am having ongoing problems with Flash Player. Every time I start Firefox it is telling me that I must update to the latest version of Flash Player but every time I try to do that it fails. I get a top bar message which says, in effect, you need a plugin (not mentioned) to view the content on this page but the install button does not work.

    Adobe/Flash website help is of little or no use as it takes you right round in a loop to exactly the same page with the same result. Very Frustrating – I am thinking of giving up on Firefox if this continues.

    July 21st, 2010 at 06:13

  40. Cathy

    Fire Fox 3.6 crashes nearly every day, several times. I don’t know why. It never used to with 3.8. I’m tempted to go back. It was fast and never crashed like my IE 6 used to, but now it’s worse, and I’m considering uninstalling and putting either IE 8 or Google Chrome up.

    What did y’all do to this? As far as I’m concerned it was fine the way it was before 3.6.10

    Disgruntled User

    October 14th, 2010 at 16:17

  41. Kelly

    I run Windows 7 with the newest version of FF, and having the same issues. Have constant issues of “Mozilla Not Responding” Happens every 15mins or so, and if you push it I get a lovely white screen. Have done a complete clean of my system and have reinstalled Mozilla and the flash player with absolutely no luck.
    Getting very frustrated with FF and Windows 7. Come-on guys., Stop dropping new crap on to the market with testing it first, What are you going through cutback and don’t have enough people to beta test these programs.

    If anyone comes up with a solution to this problem, drop me a line. I would appreciate it. (before my new computer becomes a boat anchor)

    October 16th, 2010 at 11:09

  42. Amanda

    My FF is constantly going to the white screen as well. I really don’t want to use another browser but this is getting ridiculous. It just did it again while I was typing this message. :(

    October 22nd, 2010 at 11:30

  43. itest

    In my case, we build customized xulrunner ( of ) and it is used as a native browser in our application we see random crash as well. Launching browser to a flash site seems to be fine, but as soon as you click on those objects, cpu is packed for several seconds and UI stops responding…

    October 28th, 2010 at 16:32

  44. Six Shooter Sally

    FireFox…I am going back to Internet Explorer until I hear of a fix for the problems on F/F 3.6.12. I am tired of it crashing and not being able to update Flash Player.
    Please let me know when the problems are resolved so I can switch back.

    November 24th, 2010 at 12:15

  45. Diana

    Thank God! A place I can air my FF grievances. Ever since i installed the latest update–3.6.12–websites are displaying all weird…?? It crosses out tabs on my Yahoo mail page, and simply doesn’t show all the graphics on others. I know it’s Mozilla, because, on Internet Explorer, these sights display normally. Have tried numerous ‘system restores,’ and other program updates, which’ve just been a huge waste of time. Has anyone had the same problem, and been able to fix it? THANKS!

    November 30th, 2010 at 17:10

  46. fred

    I’m driven crazy with FF crashing in the new version 3.6 even went back one version but no luck… I’ve been a fan of FF for ages and I works perfectly on my son’s computer with the same add ons…
    Wonder when the new version will come out with the fixes?

    December 17th, 2010 at 05:58

  47. punita

    I am able to watch videos on safari and use You Sent It on Safari after being told by firefox 3.6.12 that the server cannot be found. What is up with this latest version that it has so many glitches? I never had this with 3.0 or 3.2 and now that some programs have forced me to upgrade, I do not have functionality with simple things like watching you tube videos from certain links and always used to work. I am not at all impressed with this new firefox version

    January 6th, 2011 at 14:59

  48. Diana C.

    I am SO with Mr. Dale Lewis, a recent commenter. I am so frustrated with Firefox, that I’ve uninstalled all 3.6 versions from my Laptop. I used to exclusively use Mozilla, as I liked it, Much More than Internet Explorer. And, the only way to get my main issue heard is through snail-mail, as, I’ve gotten absolutely NO Help from their so-called support site. I’ve asked questions a dozen differenct ways, & all I get is there is no response to them.

    I appreciate that I can air my frustrations on mozilla hacks, but do those working for Mozilla ever get our grievances–which seem like MANY?!?!

    February 10th, 2011 at 12:11

    1. Paul Rouget

      February 11th, 2011 at 00:57

  49. Joe Razz

    I’m running into computer hang problems over and over again. I am running MS Windows 7 and Firefox 3.6.13 The computer seems to hang and the browser (not responding) when running a YouTube flash movie. The hang happens if the computer is left unattended for an hour or so. The computer is running Windows 7 and it hangs so bad that only a forced restart will fix it. Could this be a FF/Flash memory leak? Is there any thing I can do to help the FF community of developers analyze the problem?

    February 27th, 2011 at 07:53

  50. Carol J.

    I have been having a lot of issues with FF 3.6.13 for awhile now. It is slow….does not respond and today it crashed again. I think awhile ago today I say an update for it but I`m not sure I want FF anymore.It is really getting slow !! What is up with this? I can play on Pogo fine but when it comes to FB it is giving me a lot of problems .

    March 5th, 2011 at 13:57

  51. M. Diana Castello

    Honestly, when I first made a comment, I was hoping to be sent a solution–at least, a suggestion…?! How do I do this?? When I’ve gone directly to the FF site, and ask for technical help, it comes back with zero responses. I’ve tried asking, at least a dozen different ways.
    When I hit their ‘contact’ link, there’s only several addresses (not email), where you can snail-mail them a question–how not modern…and inconvenient!!
    Originally, Mozilla was my default browser. Now, I’m so frustrated, I simply don’t use it, at all! You’d think they’d want to know this.

    March 7th, 2011 at 16:40

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