Web Technologies Polyfill

Palefill Rules

Palefill internally uses a rule system inspired by Adblock to specify what rules are applied to sites. This allows adding new fixes by writing very little code.

Rule Syntax

Rules are made up of two parts: at least one selector and at least one fix.

Fixes can be any number of actions, best refer to function evaluateFix for up-to-date info on what each one does. The names are case-sensitive.

Selectors use a syntax derieved from Adblock filters. Three parts are used:

All of these are valid selectors:

Rule scripts are constructed by giving any number of selectors followed by a comma-separated list of the fixes to apply, indented by whitespace:

Additionally, the exclusion script has a special case: if the special fix * is used, all fixes are suppressed for the matched sites. This is useful when running this add-on alongside others that also apply changes. For example, the following rule disables all fixes on

GitLab Rules

Since there are many self-hosted GitLab instances that all need the same fixes as the “official”, a split approach is used for these: a list of well-known instances is shipped with the add-on and additionally, it is possible to specify custom URLs in the add-on’s preferences. This makes it easy to i.e. add private instances that don’t need to be in the global list.

Builtin definitions