eventctrlKey

event.ctrlKey is a boolean property of input events in web browsers that indicates whether the Control key was pressed when the event occurred. It is available on KeyboardEvent and MouseEvent (and related event interfaces) and is true if the Control key was held down during the event, otherwise false. The property is commonly used to implement keyboard shortcuts such as Ctrl+C or Ctrl+S, as well as modifier-based behavior in mouse interactions.

Cross-platform considerations are important because macOS users typically use the Command key instead of Control. To support a consistent shortcut experience across platforms, developers often check both ctrlKey and metaKey, for example by evaluating if (event.ctrlKey || event.metaKey).

Usage notes: The property is evaluated for the duration of the event and reflects the presence of the Control modifier during that event. It is false by default for events where the Control key was not involved. It enjoys wide support across major browsers and is part of standard event interfaces.

Common patterns: In a keydown handler, check event.ctrlKey to trigger a shortcut route; combined with other keys (for example, event.ctrlKey && event.key === 'c') to detect specific combinations. For cross-platform compatibility, many implementations combine ctrlKey and metaKey checks to cover both Windows/Linux and macOS environments.

See also: metaKey, key, and the broader KeyboardEvent and MouseEvent interfaces.