WheelEvent class

The WheelEvent interface provides specific contextual information associated with wheel events. To create an instance of the WheelEvent interface, use the WheelEvent constructor, passing an optional WheelEventInit dictionary.

Inheritance: WheelEvent → MouseEvent → UIEvent → Event → DOMObject

The WheelEvent type exposes the following members:

Constructors

Constructor	Description
init	Initializes a new instance of the `WheelEvent` class.

Properties

Property	Description
bubbles	Used to indicate whether or not an event is a bubbling event. If the event can bubble the value is true, else the value is false.
cancelable	Used to indicate whether or not an event can have its default action prevented. If the default action can be prevented the value is true, else the value is false.
current_target	Used to indicate the `IEventTarget` whose `IEventListener`s are currently being processed. This is particularly useful during capturing and bubbling.
event_phase	Used to indicate which phase of event flow is currently being evaluated.
target	Used to indicate the `IEventTarget` to which the event was originally dispatched.
time_stamp	Used to specify the time (in milliseconds relative to the epoch) at which the event was created. Due to the fact that some systems may not provide this information the value of timeStamp may be not available for all events. When not available, a value of 0 will be returned. Examples of epoch time are the time of the system start or 0:0:0 UTC 1st January 1970.
type	The name of the event (case-insensitive). The name must be an XML name.
default_prevented	Returns true if preventDefault() was invoked while the cancelable attribute value is true, and false otherwise.
is_trusted	The isTrusted attribute must return the value it was initialized to. When an event is created the attribute must be initialized to false.
NONE_PHASE	Events not currently dispatched are in this phase.
CAPTURING_PHASE	The event is currently being evaluated at the target `IEventTarget`.
AT_TARGET_PHASE	The current event phase is the capturing phase.
BUBBLING_PHASE	The current event phase is the bubbling phase.
view	The view attribute identifies the Window from which the event was generated. The un-initialized value of this attribute MUST be null.
detail	Specifies some detail information about the Event, depending on the type of event.
screen_x	The horizontal coordinate at which the event occurred relative to the origin of the screen coordinate system.
screen_y	The vertical coordinate at which the event occurred relative to the origin of the screen coordinate system.
client_x	The horizontal coordinate at which the event occurred relative to the viewport associated with the event.
client_y	The vertical coordinate at which the event occurred relative to the viewport associated with the event.
ctrl_key	Refer to the ctrlKey attribute.
shift_key	Refer to the shiftKey attribute.
alt_key	Refer to the altKey attribute.
meta_key	Refer to the metaKey attribute.
button	During mouse events caused by the depression or release of a mouse button, button MUST be used to indicate which pointer device button changed state.
buttons	During any mouse events, buttons MUST be used to indicate which combination of mouse buttons are currently being pressed, expressed as a bitmask.
related_target	Used to identify a secondary EventTarget related to a UI event, depending on the type of event.
delta_x	In user agents where the default action of the wheel event is to scroll, the value MUST be the measurement along the x-axis (in pixels, lines, or pages) to be scrolled in the case where the event is not cancelled. Otherwise, this is an implementation-specific measurement (in pixels, lines, or pages) of the movement of a wheel device around the x-axis.
delta_y	In user agents where the default action of the wheel event is to scroll, the value MUST be the measurement along the y-axis (in pixels, lines, or pages) to be scrolled in the case where the event is not cancelled. Otherwise, this is an implementation-specific measurement (in pixels, lines, or pages) of the movement of a wheel device around the y-axis.
delta_z	In user agents where the default action of the wheel event is to scroll, the value MUST be the measurement along the z-axis (in pixels, lines, or pages) to be scrolled in the case where the event is not cancelled. Otherwise, this is an implementation-specific measurement (in pixels, lines, or pages) of the movement of a wheel device around the z-axis.
delta_mode	The deltaMode attribute contains an indication of the units of measurement for the delta values. The default value is DOM_DELTA_PIXEL (pixels).
DOM_DELTA_PIXEL	The units of measurement for the delta MUST be pixels. This is the most typical case in most operating system and implementation configurations.
DOM_DELTA_LINE	The units of measurement for the delta MUST be individual lines of text. This is the case for many form controls.
DOM_DELTA_PAGE	The units of measurement for the delta MUST be pages, either defined as a single screen or as a demarcated page.

Methods

Method	Description
get_platform_type	This method is used to retrieve ECMAScript object Type.
init_event	The `Event.init_event` method is used to initialize the value of an `Event` created through the `IDocumentEvent` interface.
prevent_default	If an event is cancelable, the `Event.prevent_default` method is used to signify that the event is to be canceled, meaning any default action normally taken by the implementation as a result of the event will not occur.
stop_propagation	The `Event.stop_propagation` method is used prevent further propagation of an event during event flow.
stop_immediate_propagation	Invoking this method prevents event from reaching any event listeners registered after the current one and when dispatched in a tree also prevents event from reaching any other objects.

WheelEvent class

WheelEvent class

Constructors

Properties

Methods

See Also