Dynamic filtering: rule syntax

Type-based rules

Type-based rules are used to filter specific types of request on a web page. There currently exists five types of request which can be dynamically filtered:

• images
• inline scripts
• 1st-party scripts: scripts which are pulled from the same domain name of the current web page
• 3rd-party scripts: scripts which are pulled from a different domain name than that of the current web page
• 3rd-party frames: frames elements which are pulled from a different domain name than that of current web page

These rules can apply everywhere, or be specific to a web site. For instance blocking 3rd-party frames is a very good habit security-wise: * * 3p-frame block. This rule translates into "block 3rd-party embedded frames everywhere".

Another example: wired.com * image block, which means "block all images when visiting a web page on wired.com".

Hostname-based rules

Hostname-based rules are used to filter network resources according the their origin, i.e. where they come from. Hostname-based rules have a higher specificity than type-based rules, and thus hostname-based rules always override type-based rules whenever a network request end up matching both a type- and a hostname-based rule.