The MouseEvent interface represents events that occur due to the user interacting with a pointing device (such as a mouse). Common events using this interface include click, dblclick, mouseup, mousedown.
The KeyboardEvent.code property represents a physical key on the keyboard (as opposed to the character generated by pressing the key). In other words, this property returns a value which isn't altered by keyboard layout or the state of the modifier keys.
The MouseEvent.ctrlKey read-only property returns a Boolean that indicates if the control key was pressed (true) or not (false) when the event occured.
The MouseEvent.getModifierState() method returns the current state of the specified modifier key: true if the modifier is active (i.e., the modifier key is pressed or locked), otherwise, false.
The MouseEvent.region read-only property returns the id of the canvas hit region affected by the event. If no hit region is affected, null is returned.