Filter syntax extensions

µBlock supports most of Adblock Plus filter syntax. However µBlock does not support some very specific case, and also added its own extensions to ABP filter syntax.

Not supported

Regular expression-based filters: may add according to demand, but if ever I add support for regex-based filters, I will support only for regexes which can be tokenized, or which are specific to a hostname, i.e. regexes which can be implemented in an efficient way.

Extended syntax

µBlock extends Adblock Plus filter syntax.

Network filters

The important network filter option: The important filter option, important, means to ignore all exception filters. It applies only to net block filters. The important option will allow you to block with 100% certainty specific net requests. Example: ||google-analytics.com^$important,third-party will block all net requests to google-analytics.com, disregarding any existing network exception filters. Another example: ||twitter.com^$important,third-party. Etc.

The inline-script network filter option: To specifically disable inline script tags in a main page: ||example.com^$inline-script.

Cosmetic filters

Entity-based cosmetic filters: Filters which are to be applied to a specific entity. An entity is defined as follow: a formal domain name with the Public Suffix part replaced by a wildcard. Examples: google.* will apply to all similar Google domain names: google.com, google.com.br, google.ca, google.co.uk, etc. Another example: facebook.* will apply to all similar Facebook domain names: facebook.com, facebook.net.