WheelEvent

The WheelEvent interface represents events that occur due to the user moving a mouse wheel or similar input device.

Important: This is the standard wheel event interface to use. Old versions of browsers implemented the non-standard and non-cross-browser-compatible MouseWheelEvent and MouseScrollEvent interfaces. Use this interface and avoid the non-standard ones.

Do not confuse the wheel event with the scroll event: The default action of a wheel event is implementation-defined. Thus, a wheel event doesn't necessarily dispatch a scroll event. Even when it does, that doesn't mean that the delta* values in the wheel event necessarily reflect the content's scrolling direction. Therefore, do not rely on delta* properties to get the content's scrolling direction. Instead, detect value changes to scrollLeft and scrollTop of the target in the scroll event.

Constructor

WheelEvent()
Creates a WheelEvent object.

Properties

This interface inherits properties from its ancestors, MouseEvent, UIEvent, and Event.

WheelEvent.deltaXRead only
Returns a double representing the horizontal scroll amount.
WheelEvent.deltaYRead only
Returns a double representing the vertical scroll amount.
WheelEvent.deltaZRead only
Returns a double representing the scroll amount for the z-axis.
WheelEvent.deltaModeRead only
Returns an unsigned long representing the unit of the delta* values' scroll amount. Permitted values are:
Constant Value Description
WheelEvent.DOM_DELTA_PIXEL 0x00 The delta* values are specified in pixels.
WheelEvent.DOM_DELTA_LINE 0x01 The delta* values are specified in lines.
WheelEvent.DOM_DELTA_PAGE 0x02 The delta* values are specified in pages.

Methods

This interface doesn't define any specific methods, but inherits methods from its ancestors, MouseEvent, UIEvent, and Event.

Specifications

Specification Status Comment
UI Events
The definition of 'The WheelEvent interface' in that specification.
Working Draft
Document Object Model (DOM) Level 3 Events Specification
The definition of 'WheelEvent' in that specification.
Obsolete Initial definition.

Browser compatibility

BCD tables only load in the browser

See also