US Patent 11385772 Attribute-based rules for displaying additional information

A storage unit stores a rule for specifying additional information to be displayed for each operation scene identified with a combination of states of DOM elements of a predetermined web page being represented by presence/absence or attribute values. A rule interpretation execution unit monitors the states of the DOM elements of the predetermined web page, and causes the storage unit to store the states as a context board. The rule interpretation execution unit displays, if states of the operation scene matching states of the context board stored in the storage unit, the additional information specified with the rule.