Like Mozilla's built-in image blocker, Adblock Plus blocks
HTTP and
HTTPS requests according to their source address and additional context information and can block
iframes,
scripts, and
Flash. It also uses automatically generated user
stylesheets to hide elements such as text ads on a page as they load instead of blocking them, known as element hiding.
Android On rooted devices, the Android app blocks ads on all
web traffic including mobile networks. For non-rooted devices, ads are only blocked through a
Wi-Fi connection and requires the user to set up a local
proxy server for each network in order for the app to function. The app uses a local proxy server to intercept web traffic and remove ads before showing content to the user. Most of the content that users are trying to block will be removed, though some content is missed, and the app is not as reliable at blocking ads as the browser versions. The app can be configured to auto-start every time the device reboots, minimizing the action required by the user.
Filters Basic filter rules can include wildcards represented by asterisks (*). Sites and objects can be whitelisted with filters that start with two
at signs (@@).
Regular expressions delimited by slashes (/) can be used by advanced users. Adblock Plus also supports a more-sophisticated syntax that gives fine-grain control over filters. An example of the sophisticated filtering would be wikipedia.org##div#centralNotice, which will hide the centralNotice element used by Wikipedia to display donation requests. The first part of the filter is the
domain name, followed by two pound signs, and a
CSS selector. This type of filtering is called cosmetic filtering, as it hides parts of the website after it has loaded. Both
uBlock Origin and
AdGuard's browser extension and apps also support this type of filtering.
Filter subscriptions Users can add external filtersets. Adblock Plus includes the ability to use one or more external filter subscriptions that are automatically updated.
Filterset.G is incompatible with this system (and Adblock Plus specifically recommends against using Filterset.G for other reasons as well), but other filtersets can be added by typing their addresses. A list of known Adblock Plus subscriptions is maintained on the Adblock Plus
official website. EasyList was the most popular Adblock Plus filter list as of August 2011, with over 12 million subscribers. Created by Rick Petnel, it became officially recommended by the Adblock Plus program, and filter lists for other languages were built on top of it. Petnel died in 2009 following which Palant placed a user named "Ares2" as the new maintainer. The filter lists EasyList and EasyPrivacy are both subscribed by default in
uBlock Origin but not in Adblock Plus itself. Both of these filter lists will also be used by Google Chrome starting February 15, 2018, on sites not complying with the Better Ads Standards. In May 2013, the former second most popular Adblock Plus filter list, Fanboy's List, was merged with EasyList.
Legal challenges In December 2014, it was reported that
Zeit Online and
Handelsblatt had brought suit against Eyeo GmbH in the . In April 2015 the court rejected the suit.
Axel Springer SE has filed a court order for the removal of the Adblock Plus post though there is a redacted version and people have posted videos and posts on how to get around the Axel Springer wall. However, in April 2018, Germany's
Federal Constitutional Court found in favour of Eyeo and ruled that Adblock Plus did not violate any laws. In August 2017, the Admiral advertising company sent a
Digital Millennium Copyright Act (DMCA) takedown notice to EasyList to remove the domain
functionalclam.com from the blacklist. Admiral argues that the domain is part of its access control technology of its advertising platform, and therefore the blacklisting is an attempt to circumvent a technical protection measure, which is forbidden under the DMCA section 1201. ==Detection==