selectors.register(name, script[, options])

• script <|string|> Script that evaluates to a selector engine instance.
  • path <string> Path to the JavaScript file. If is a relative path, then it is resolved relative to .
• options <Object>
  • <> Whether to run this selector engine in isolated JavaScript environment. This environment has access to the same DOM, but not any JavaScript objects from the frame’s scripts. Defaults to false. Note that running as a content script is not guaranteed when this engine is used together with other registered engines.

An example of registering selector engine that queries elements based on a tag name: