An embedded macro establishes logic for object properties that define actions that execute when an event triggers. When an embedded macro is associated with an event, a regular event property value is set to an empty string and a shadow property associated with the regular event property is created. An application that supports embedded macros recognizes the empty regular property value as an indicator that a macro is embedded in the event. A binary representation of the macro is accessed from the shadow property and is executed when the event associated with the embedded macro triggers. An action safe list identifies trusted embedded macro actions. Embedded macro actions not included on the safe list are not executed such that untrusted actions are blocked from execution.