Adblock Plus and (a little) more

Adblock Plus for Google Chrome to be released soon · 2010-12-15 18:52 by Wladimir Palant

For a while my official position on Adblock Plus for non-Gecko browsers read like this:

Forget it, I am not writing Adblock Plus from scratch just to support your favorite browser (be it Chrome or Safari or Opera or Internet Explorer). And even if somebody gives me the code — I am not going to maintain two unrelated projects. This asks for an independent project and in fact, there are already independent projects to implement ad blocking for all of these browsers.

As you can read from this, the frequent requests to port Adblock Plus to <insert your favorite browser here> got quite annoying. Still, it is time to change this position, we are starting to look into ways to cover other browsers than Firefox and SeaMonkey. And we are starting with Google Chrome, a beta version of Adblock Plus for Google Chrome is scheduled to be released soon. I’ll try to give answers to some questions that you are certainly urging to ask.

What changed now, why are you doing that?

The declared goal of the Adblock Plus project is changing the internet as a whole and putting users back in control. We came to the realization that while Firefox is and stays very important being restricted to only one major browser limits our options too much. We continue to consider partnering with other ad blocking projects but these projects have very different goals that are difficult to align with ours. This very clearly manifests itself in the configuration capabilities that these extensions offer: there are typically only rudimentary configuration options, the focus is instead on reusing filter lists that have been created for Adblock Plus. The result is that contributing back to the filter lists is only possible for Adblock Plus users, users of other extensions are lost for our community.

Why start with Chrome and not Internet Explorer?

Internet Explorer with its still very significant market share would be a primary target — if it had a usable extension support. Unfortunately, not much has changed in the three years since my blog post on this topic, creating an ad blocker for Internet Explorer is still an ugly and very complicated business. We have some ideas but it will take a while to implement those.

As to Chrome, it supports JavaScript-only extensions and we hope to reuse much of the Adblock Plus source code. What’s even more important, recent Chrome versions allow extensions to block downloads. This functionality is still incomplete but we hope that the remaining holes will be closed in future. And finally, porting a Chrome extension to Safari seems relatively simple.

Did you write a new Chrome extension from scratch?

No. We were talking to Tom Joseph, the developer of AdThwart. He didn’t have time to continue AdThwart development so he agreed to hand over the project to us which we will continue under a new name (Adblock Plus for Google Chrome) while keeping the existing users. So we get to start with an existing and relatively small codebase which already reuses parts of the Adblock Plus source code. And we win Tom Joseph as a contributor.

What has been done already? What is planned?

I have to state first: Chrome’s extension system has severe limitations, so we won’t be able to create an exact equivalent of Adblock Plus for Firefox. However, there is still much we can improve to make Adblock Plus for Chrome behave more similar to the Firefox version. What has been done so far:

  • Extension has been rebranded into “Adblock Plus for Google Chrome (Beta)”.
  • The source code has been made available under the Mozilla Public License 1.1, code parts that couldn’t be relicensed were either removed or rewritten.
  • A mechanism to automatically rewrite Adblock Plus source code has been created to make that code suitable for Chrome. The one year old Adblock Plus code in AdThwart has been updated and should stay in sync with current Adblock Plus development now.
  • A few minor issues have been fixed to make Adblock Plus for Chrome behave more consistently (most importantly: it will work correctly with XHTML documents now).

We want to release Adblock Plus for Chrome with these changes and continue with other changes then:

  • Make it reuse more of the Adblock Plus core code, especially to make it match Adblock Plus behavior more closely.
  • Block more advertisement downloads that are currently only being hidden.
  • Remove known inconsistencies and shortcomings where possible.
  • Redesign the user interface along the lines of what is planned for Adblock Plus 1.4.

I also expect development builds to be available soon so that you can test drive these changes before they are officially released and give us your feedback.


Comment [53]

  1. Wok · 2010-12-15 19:22 · #

    I first thought it was April Fools’ Day. Really interesting to follow this project!

  2. pirlouy · 2010-12-15 19:26 · #

    I think it’s a huge announcement…

    But do you think you’ll be able to keep advanced filters like blocking third party script only ? Or display content list?

    Not a good news for Mozilla however.

    Reply from Wladimir Palant:

    Third-party flag is actually a relatively easy target. AdThwart already has a primitive version of this check – but it has problems recognizing the top-level domain properly. The required functionality doesn’t exist in Chrome but fortunately, Mozilla made both the data and the algorithm public:

    Blockable items list is more complicated. Storing URLs that have been found shouldn’t be too hard, it is only creating a usable UI for the data that will be problematic.

    As I said, we won’t be able to create an exact equivalent. But we can still create something that will work pretty well.

  3. S · 2010-12-15 22:49 · #

    Already removed AdBlock for Chrome and changed to AdThwart when I saw the news…


  4. tiik · 2010-12-15 23:54 · #

    Hope it can be the best X’mas gift from adblock plus!

  5. msm · 2010-12-16 00:30 · #

    Will it work with JavaScript disabled?

    Reply from Wladimir Palant:

    That’s up to Chrome developers – it is a Chrome limitation, not something extensions can change.

  6. Cider · 2010-12-16 01:12 · #

    Great! Finally I will be able to choose from more than one browser again!

    Thank you very much!

  7. Darren · 2010-12-16 02:18 · #

    Have you considered an option to allow users to download ads but never render them? It doesn’t have to be the default, just an option.

    Maybe it sounds stupid but it would mean that sites would still be paid for by advertisers because they think their ad was viewed (obviously it wouldn’t have any effect on those paid based on click-throughs).

    Ideally it would be a system where URLs of blocked content were queued and then the queue would be downloaded when the internet connection was idle.

  8. MrG · 2010-12-16 05:07 · #

    great news!

  9. Kevin · 2010-12-16 06:21 · #

    how is this possible if is not fixed yet?

    Reply from Wladimir Palant:

    It would be nice to see that fixed – but for now the “beforeload” event introduced in WebKit will do as well, despite some shortcomings.

  10. Brian James Herman · 2010-12-16 08:27 · #

    I’ll try it with my new CR-48 notebook. Yay!

  11. Kenny McCormick · 2010-12-16 08:59 · #


    This is what it will take for me to try Chrome. I’ve been ignoring and resisting it because the ad blockers it has now fail at life compared to ABP, and I am absolutely anal about ads.

  12. Chris K · 2010-12-16 13:18 · #

    Awesome news!!!! the current adblock is just passable but in terms of ad blocking in videos, youtube 4od etc, it completely fails, sometimes you have to disable adblock just to watch the video as it just blocks the whole thing. nightmare.

    As long as your chrome adblock does video ad blocking as well as the firefox one im sold!

    keep up the awesome work man!

    Reply from Wladimir Palant:

    I will do as much as Chrome lets me do – and blocking inside videos is pretty much impossible right now, that’s not the fault of the extension.

  13. lovelywcm · 2010-12-16 13:46 · #

    How about webRequest.onBeforeRequest?

    Reply from Wladimir Palant:


    “Also, the Chrome Developer Dashboard doesn’t allow you to upload extensions that use experimental APIs.”

    So it is a nice API but we will have to wait for it to be released. Right now we cannot use it.

    Reply from Wladimir Palant:

    PS: As implemented right now this API can only be used for logging, it cannot actually prevent a request. The proposal has some discussion on allowing blocking to happen but it is unclear whether that will ever be implemented.

  14. kalamagwi · 2010-12-16 14:26 · #

    Heh, so still no chances for the Adblock Plus for Opera? That’s quite sad.

    Reply from Wladimir Palant:

    Still waiting for Opera to introduce some way to block downloads.

  15. Markus · 2010-12-16 17:01 · #

    Fantastic news. Lack of proper adblocking that is, like ABP does it is one of the factors that so far has kept me from using Chrome (or rather, Iron) more often. Inquiring minds want to know though:
    -Will it work with Chrome forks? Most importantly Iron, which has rudimentary adblocking built in (similar to Opera’s urlfilter.ini approach, but lacking wildcards).
    -Will it use the exact same rule syntax as Firefox ABP?
    -Will it feature the same functionality, most notably collapsing of elements, and hitcount stats for each rule the way it works in Firefox?

  16. Maicon · 2010-12-16 18:16 · #

    A version for the new Opera 11 would be great too :)

  17. LorenzoC · 2010-12-16 18:36 · #

    I am using exactly the same filter list for ADBP (dev build) on Firefox 4 nightly and for Block Content on Opera 11 (that works with the “ulrfilter.ini”). All I did was to add “http://” in front of ADBP rules.

    Yes, there isn’t any of the “advanced” tricks but for my own purpose I don’t need them much.

    The big plus of ADBP is the very handy GUI for inspecting the blockable objects and to write the filter rules. Unfortunately I am told that Opera 11 extensions cannot access the “ulrfilter.ini” file (I don’t know if it is true) so I guess the current extensions just set the CSS display option on “hidden” and that should make Opera to not download the element.

    Of course I’ve no idea on how much the ADBP filters in the latest implementation impact on Opera’s performance.

  18. Hail · 2010-12-17 00:37 · #

    Hello Wladimir,

    Sorry for off-topic,

    Now that Opera 11 is has been finally released,will we see ADBP extension for it soon below here,

    Hoping to see ADBP on the above list very soon :)

    Reply from Wladimir Palant:

    See reply to comment #14

  19. lovelywcm · 2010-12-17 04:31 · #

    In reply to #13

    I found webRequest.onBeforeRequest event is fired asynchronously. That made it much useless for blocking, proxy and many other situations.

  20. Aerik · 2010-12-18 06:00 · #


    When this came up on reddit, users kept dropping comments like, “why bother? I use adthwart! hurr durr”

  21. bingvsadthwart · 2010-12-18 09:31 · #

    Hi Wladimir, I’m very happy about this news! So as long as you’re doing all the dirty work to convert AdThwart to Adblock Plus, please make sure to eliminate AdThwart’s severely annoying “page flash” syndrome on unfiltered pages. For example, if you go to, and type in a city name and scroll the map around, you’ll see that it flashes constantly, even with AdThwart disabled for the page. Same with Picasa Web Albums. This problem is so annoying that it almost nullifies AdThwart’s benefits for users of image-manipulating sites. It seems like AdThwart is doing some rerendering logic before even asking the question as to whether it should do anything at all based on the domain name.

    Reply from Wladimir Palant:

    This “page flash” syndrome is there to eliminate an even worse flashing if ads are hidden after the fact. This is due to a Chrome limitation, when the page starts loading the blocking script needs to request ad blocking preferences which might take some time. Until that is done the script doesn’t know whether it is enabled or what needs to be blocked. I can think of some things that will improve the situation but I doubt that the issue can be solved entirely.

  22. Lanel · 2010-12-18 10:57 · #

    This is great news. AdThwart has always been excellent, and now it will get even better. :] You made a right choice teaming up with Tom Joseph. He’s one of the rare “good developers” that users wish to have programming their add-ons/ extensions.

  23. Mxx · 2010-12-18 11:18 · #

    Would it be possible to integrate with Chrome’s native content blocking?

    Reply from Wladimir Palant:

    No, Chrome doesn’t allow that right now. Maybe if the Chrome developers improve the APIs.

  24. G4Oblivion · 2010-12-18 16:04 · #

    Sounds awesome!

    I switched from Firefox to Chrome almost a year ago.
    Adblock Plus is by far my most missed extension.
    The current adblocking extensions for Chrome have problems and seriously slow down my browser.

    Thank you very much. I’m looking forward to it.

  25. Famlam · 2010-12-18 20:00 · #

    I can’t keep my mouth shut :)
    Good luck!
    Famlam (AdBlockforChrome)

  26. James Edward Lewis II · 2010-12-19 06:48 · #

    For the people who said that there hasn’t been a Chrome ad-blocking extension that blocks content rather than hiding it, both AdThwart and AdBlock for Chrome have been doing it for several months (ever since Chrome made use of a WebKit update that gave it the necessary infrastructure), although it doesn’t work perfectly well the way it does in Safari and long has in Firefox.

    Also I find it sad that although there is a way to natively add urlfilter.ini entries manually in Opera even while it is running (the Blocked Content menu), Opera extensions cannot yet do that…

  27. armv · 2010-12-19 06:55 · #

    Any ETA on when the extension is going to be available?

    Reply from Wladimir Palant:

    First release is going to be tomorrow or the day after, the development build is already available ( This release will be only a minor improvement over AdThwart 1.0.20 however, we didn’t start implementing the serious changes yet.

  28. Julius · 2010-12-19 09:44 · #

    hey,the people will be confused if there is a 2 “adblock”.one is developed by Michael Gundlach and one from Wladimir Palant!

    Reply from Wladimir Palant:

    People are already confused – I had to add a message to our forum that would be displayed to Chrome users, they kept asking for assistance here rather than in Michael Gundlach’s Google group. It’s too bad that Michael chose this misleading name for his extension but it isn’t something we are able to change now.

  29. congrats · 2010-12-19 16:14 · #

    congrats for killing the web.
    95% of webmasters out there can maintain theirs website only with ads.

    blocked ads = dead website

    congrats again, only very smart people can make such awful tools

  30. wtf · 2010-12-19 18:03 · #

    oh really? so tell them to make the ads less annoying.

  31. please · 2010-12-19 21:53 · #

    Interestingly, the web appears to be alive and kicking. I make a point to whitelist sites that I like and visit frequently, provided they don’t make use of flash ads which are not only annoying but an utter waste of bandwidth and resources.

    I look forward to testing out ABP for Chrome as I very much like the browser and would like to get some functional ad-blocking in it. Unfortunately it appears that this will be limited by chrome itself so here’s hoping this will be improved in future.

  32. chris · 2010-12-20 02:05 · #

    Thank you for making ABP for Chrome. This is the only thing that is making me stay with FF

  33. Kevin · 2010-12-20 03:51 · #

    Now that AdThwart will become Adblock Plus for Google Chrome, where should I report bugs? Or should I wait for the next version before filing new bugs?

    Reply from Wladimir Palant:

    In the Adblock Plus forum – a section for Google Chrome users has been created already.

  34. Ben · 2010-12-20 14:49 · #

    Any intention to make it be able to block website popups?

    Reply from Wladimir Palant:

    As far as I know, neither Firefox nor Chrome currently offer a good way to do this.

  35. Lozzy · 2010-12-20 21:59 · #

    @ Ben/Comment #34;

    There is already a companion addon which apparently helps to deal with popups;

    I haven’t tried it but the reviews seem to suggest that it works.

  36. Kees · 2010-12-21 01:00 · #

    Hey guys… excellent work… but the icon is really scary! Could you please give us the option to get the old icon back in the chrome extension. It really kicked a$$!
    Keep up the good work!

  37. blah · 2010-12-21 01:53 · #

    “Adblock Plus for Google Chrome” is long and ugly. how about adblock plus gc, adblock plus ff, adblock plus sf, and adblock plus ie. that’s all 4 main browsers. i’d changed the “plus” to a ““ also (Adblock FF), but that’s just me. i like concise and consistent names.

    Reply from Wladimir Palant:

    It has to be “for Google Chrome” according to Google’s naming rules.

  38. blah · 2010-12-21 01:55 · #

    in my above post, the plus symbol apparently can’t be posted and causes some weird underlining instead.

  39. dan · 2010-12-21 14:36 · #

    Adb plus is not working like ADThwart was doing.At chrome start extension does not show up then i have to uninstall and install again to work. But when browser is closed at reopening the same problem appear.

    Reply from Wladimir Palant:

    I guess that “extension doesn’t show up” means “ABP icon doesn’t show up”? I think that there was only one relevant change – that icon no longer shows up for pages from disk and such (where Adblock Plus cannot do anything anyway), only for actual web pages. Is that the issue? If not – you better start a topic in the forum, your report doesn’t have enough information to understand the problem.

  40. dan · 2010-12-21 16:06 · #

    i will be more detailed.I use chrome 10.AdBlock plus is installed.Subscription filter list for my region is added.I browse webpages and adds are not blocked.I uninstall ADblock plus
    and reinstall again without closing browser.Icon show up in right corner ,start browsing same webpages and adds are blocked this time. Everything is ok.When i close the browser and restart it again the icon from top right is gone and the adds on the same webpages are not blocked anymore.

    Reply from Wladimir Palant:

    It seems that there is a forum topic on this issue already:

    Please feel free to participate there and to supply more information: which filter subscription is added and what webpage we can try to reproduce this problem.

    Reply from Wladimir Palant:

    Never mind, after guessing that you were subscribed to ROList I could reproduce this issue. Update is coming shortly.

  41. Michael Will · 2010-12-21 21:49 · #

    Previously a Firefox user, I was a huge fan of AdBlock Plus. In fact it was hard for me to switch to Chrome when there was nothing even close.

    AdBlock and AdThwart always were decent competitors. I went with AdBlock recently when their 2.0 version started blocking ads from downloading rather than just hiding them.

    What does the renamed AdThwart bring to the table in this aspect? Is this one area you admit AdBlock has the lead in currently, and something you will strive to remedy? Or is my understanding of the pros and cons between these 2 extensions lacking?

    Reply from Wladimir Palant:

    Adblock Plus for Chrome already blocks a decent number of ad servers (significantly more than AdThwart though we had a temporary setback here – It is still only hiding on some occasions, that’s something that I plan to fix in the next release, hopefully not at the expense of performance (it appears that the current intermediate blocking solution is the reason why AdThwart was faster than Adblock).

  42. Lanel · 2010-12-22 05:13 · #

    @ Mxx

    This is a very good extension that’s already made which can handle pop-ups well on Chrome: (Better Pop Up Blocker)

  43. Øyvind · 2010-12-22 13:58 · #

    I am very close to uninstalling Adblock Plus just because you changed the name. AdThwart was ten times cooler, and you had that awesome icon. You really shouldn’t underestimate the power of a cool brand name/image. This new logo just angers me. Looks just like Adblock.

  44. EP · 2010-12-25 00:35 · #

    Hey Wladimir. It’s kinda neat that you now have an Adblock Plus extension for Chrome even though it hasn’t been finalized yet.

    You could try to get in touch of the creator of Adblock for Safari to get some ideas on how to port ABP into Safari:

    Reply from Wladimir Palant:

    He also happens to be the author of Adblock for Chrome ;)

    Porting to Safari isn’t a question of “how” but rather a question of “when”. I think that we need Adblock Plus for Chrome to work properly first.

  45. Sean C · 2010-12-26 20:14 · #

    Will Adblock Plus for Chrome be able to eventually block ads that appear at the beginning of online videos, or is this a limitation of Chrome?

    For example, every time I want to view a video on I am forced to watch a 30 second video. Sometimes the videos I want to watch (highlights) aren’t even 30 seconds long! 1:1 video:advertisement ratio is ridiculous! :)

    Thank you!!

    Reply from Wladimir Palant:

    It is currently a limitation of Chrome.

  46. Alvin Polk · 2010-12-29 05:31 · #

    Aw! I miss the little devil icon!

  47. ntr · 2011-01-09 21:47 · #

    Why there is no verified author anymore for the adblock plus extension for google chrome ?

    Reply from Wladimir Palant:

    I don’t know – Google was still unable to transfer the extension to my account. Maybe Tom Joseph removed it so that user’s aren’t confused by a site unrelated to

  48. Jeanne · 2011-01-10 18:43 · #

    Any estimate on when we will have a product close to Firefox’s

    Reply from Wladimir Palant:

    Depends on what you mean. Having better blocking and more reuse of Adblock Plus code should be done in a month. Better user interface and proper configurability – this can take a while.

  49. dan · 2011-01-12 16:57 · #

    you doing great work with ADB plus. I enjoy using that but i have a problem.I subscribed to RO List.Only on the folowing webpage ADB plus is causing an error. when ADb plus is disabled everything is ok no error. The error is : When click on a news link to open in new tab i get the next message:
    jcarousel: No width/height set for items.This will cause an infinit loop. Aborting… Then i click on ok and i get the same message as above and Prevent this page from creating additional dialogs,i thick that box and click ok.Now all is ok for this tab but if open new tab i have to do that again. Can you figure out what the problem is

    Reply from Wladimir Palant:

    This is a bug in the jCarousel script which has been fixed already – but the website uses the old version of the script, feel free to notify the webmaster about that. I forwarded your report to the RoList authors, I guess that they will fix it shortly. In the meantime, disabling the filter will make the website work correctly again.

  50. Andrew · 2011-01-14 01:24 · #

    You’re all deluded. You’re stealing revenue from content providers and will drive down people’s willingness to provide free content. Shooting content consumers in the foot really. The sooner someone sues the better.

  51. iNsuRRecTiON · 2011-01-23 13:53 · #

    Hi there,

    nice to hear that.

    Is the blocking inability of Chrome true to any version (nightly, alpha, dev-versions, etc.) or only to the “stable” release and beta versions?
    So even the latest unstable dev version of chrome 10 does not support proper blocking of content with the api for extensions?

    And what is about IE9, is the situation any better there?



    Reply from Wladimir Palant:

    There are currently no relevant differences between Chrome versions, they all have a limited support for blocking resources. There are some limitations, e.g. blocking XMLHttpRequests or Flash subrequests isn’t possible. Adblock Plus for Chrome currently isn’t fully using these capabilities, that’s something that we need to fix on our side.

    As to IE9, from all I know it still doesn’t have anything that would allow simple extension development.

  52. iNsuRRecTiON · 2011-01-24 12:59 · #


    thanks for your answer.

    Btw. I have to be offtopic, because the other blog entry is already closed for comments..

    I think the 6 weeks automatic comments closure is too few.

    I think 6 months would be ok, or at least 3 months..

    I think you will get fewer comments, because not everybody is reading your blog day to day or week to week.

    And some good comments may will get lost, if you close the comment feature too early..

    As to forum, I think many people who are want to comment here, don’t want to register at your forum to simply leave an answer/comment/suggestion at the blog topic..

    And 6 months is still better than some years old blogs.. ;-)



    Reply from Wladimir Palant:

    See – useful comments after 6 weeks basically never happen. It is really important – creating a forum topic (without registering) or finding my email address is easy enough.

  53. iNsuRRecTiON · 2011-01-24 20:29 · #

    Yes, I already had read this and I disagree, because of that, I wrote this comment here.. ;-)

    But if you don’t have to register, it is ok though

Commenting is closed for this article.