ReadonlyaltThe KeyboardEvent.altKey read-only property is a boolean value that indicates if the alt key (Option or ⌥ on macOS) was pressed (true) or not (false) when the event occurred.
ReadonlyAT_ReadonlybubblesThe bubbles read-only property of the Event interface indicates whether the event bubbles up through the DOM tree or not.
ReadonlyBUBBLING_ReadonlycancelableThe cancelable read-only property of the Event interface indicates whether the event can be canceled, and therefore prevented as if the event never happened.
The cancelBubble property of the Event interface is deprecated. Use Event.stopPropagation() instead. Setting its value to true before returning from an event handler prevents propagation of the event. In later implementations, setting this to false does nothing. See Browser compatibility for details.
ReadonlyCAPTURING_ReadonlycharThe charCode read-only property of the KeyboardEvent interface returns the Unicode value of a character key pressed during a keypress event.
ReadonlycodeThe 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 that isn't altered by keyboard layout or the state of the modifier keys.
ReadonlycomposedThe read-only composed property of the Event interface returns a boolean value which indicates whether or not the event will propagate across the shadow DOM boundary into the standard DOM.
ReadonlyctrlThe KeyboardEvent.ctrlKey read-only property returns a boolean value that indicates if the control key was pressed (true) or not (false) when the event occurred.
ReadonlycurrentThe currentTarget read-only property of the Event interface identifies the element to which the event handler has been attached.
ReadonlydefaultThe defaultPrevented read-only property of the Event interface returns a boolean value indicating whether or not the call to Event.preventDefault() canceled the event.
ReadonlydetailThe UIEvent.detail read-only property, when non-zero, provides the current (or next, depending on the event) click count.
ReadonlyDOM_ReadonlyDOM_ReadonlyDOM_ReadonlyDOM_ReadonlyeventThe eventPhase read-only property of the Event interface indicates which phase of the event flow is currently being evaluated.
ReadonlyisThe KeyboardEvent.isComposing read-only property returns a boolean value indicating if the event is fired within a composition session, i.e., after compositionstart and before compositionend.
ReadonlyisThe isTrusted read-only property of the Event interface is a boolean value that is true when the event was generated by the user agent (including via user actions and programmatic methods such as HTMLElement.focus()), and false when the event was dispatched via EventTarget.dispatchEvent(). The only exception is the click event, which initializes the isTrusted property to false in user agents.
ReadonlykeyThe KeyboardEvent interface's key read-only property returns the value of the key pressed by the user, taking into consideration the state of modifier keys such as Shift as well as the keyboard locale and layout.
ReadonlykeyThe deprecated KeyboardEvent.keyCode read-only property represents a system and implementation dependent numerical code identifying the unmodified value of the pressed key.
ReadonlylocationThe KeyboardEvent.location read-only property returns an unsigned long representing the location of the key on the keyboard or other input device.
ReadonlymetaThe KeyboardEvent.metaKey read-only property returning a boolean value that indicates if the Meta key was pressed (true) or not (false) when the event occurred. Some operating systems may intercept the key so it is never detected.
ReadonlyNONEReadonlyrepeatThe repeat read-only property of the KeyboardEvent interface returns a boolean value that is true if the given key is being held down such that it is automatically repeating.
The Event property returnValue indicates whether the default action for this event has been prevented or not.
ReadonlyshiftThe KeyboardEvent.shiftKey read-only property is a boolean value that indicates if the shift key was pressed (true) or not (false) when the event occurred.
ReadonlysrcThe deprecated Event.srcElement is an alias for the Event.target property. Use Event.target instead.
ReadonlytargetThe read-only target property of the Event interface is a reference to the object onto which the event was dispatched. It is different from Event.currentTarget when the event handler is called during the bubbling or capturing phase of the event.
ReadonlytimeThe timeStamp read-only property of the Event interface returns the time (in milliseconds) at which the event was created.
ReadonlytypeThe type read-only property of the Event interface returns a string containing the event's type. It is set when the event is constructed and is the name commonly used to refer to the specific event, such as click, load, or error.
ReadonlyviewThe UIEvent.view read-only property returns the WindowProxy object from which the event was generated. In browsers, this is the Window object the event happened in.
ReadonlywhichThe UIEvent.which read-only property of the UIEvent interface returns a number that indicates which button was pressed on the mouse, or the numeric keyCode or the character code (charCode) of the key pressed on the keyboard.
The composedPath() method of the Event interface returns the event's path which is an array of the objects on which listeners will be invoked. This does not include nodes in shadow trees if the shadow root was created with its ShadowRoot.mode closed.
The KeyboardEvent.getModifierState() method returns the current state of the specified modifier key: true if the modifier is active (that is the modifier key is pressed or locked), otherwise, false.
The KeyboardEvent.initKeyboardEvent() method initializes the attributes of a keyboard event object. This method was introduced in draft of DOM Level 3 Events, but deprecated in newer draft. Gecko won't support this feature since implementing this method as experimental broke existing web apps (see Firefox bug 999645). Web applications should use constructor instead of this if it's available.
OptionalbubblesArg: booleanOptionalcancelableArg: booleanOptionalviewArg: WindowOptionalkeyArg: stringOptionallocationArg: numberOptionalctrlKey: booleanOptionalaltKey: booleanOptionalshiftKey: booleanOptionalmetaKey: booleanThe preventDefault() method of the Event interface tells the user agent that the event is being explicitly handled, so its default action, such as page scrolling, link navigation, or pasting text, should not be taken.
The stopImmediatePropagation() method of the Event interface prevents other listeners of the same event from being called.
The stopPropagation() method of the Event interface prevents further propagation of the current event in the capturing and bubbling phases. It does not, however, prevent any default behaviors from occurring; for instance, clicks on links are still processed. If you want to stop those behaviors, see the preventDefault() method. It also does not prevent propagation to other event-handlers of the current element. If you want to stop those, see stopImmediatePropagation().
KeyboardEventobjects describe a user interaction with the keyboard; each event describes a single interaction between the user and a key (or combination of a key with modifier keys) on the keyboard. The event type (keydown, keypress, or keyup) identifies what kind of keyboard activity occurred.MDN Reference