WheelEvent
The WheelEvent
interface represents events that occur due to the user moving a mouse wheel or similar input device.
Note: 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.
Note: 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.
Instance properties
This interface inherits properties from its ancestors, MouseEvent
, UIEvent
, and Event
.
WheelEvent.deltaX
Read only-
Returns a
double
representing the horizontal scroll amount. WheelEvent.deltaY
Read only-
Returns a
double
representing the vertical scroll amount. WheelEvent.deltaZ
Read only-
Returns a
double
representing the scroll amount for the z-axis. WheelEvent.deltaMode
Read only-
Returns an
unsigned long
representing the unit of thedelta*
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. Each mouse click scrolls a line of content, where the method used to calculate line height is browser dependent.WheelEvent.DOM_DELTA_PAGE
0x02
The delta*
values are specified in pages. Each mouse click scrolls a page of content. WheelEvent.wheelDelta
Read only Deprecated Non-standard-
Returns an integer (32-bit) representing the distance in pixels.
WheelEvent.wheelDeltaX
Read only Deprecated Non-standard-
Returns an integer representing the horizontal scroll amount.
WheelEvent.wheelDeltaY
Read only Deprecated Non-standard-
Returns an integer representing the vertical scroll amount.
Note: Element: mousewheel event has additional documentation about the deprecated properties wheelDelta
, wheelDeltaX
, wheelDeltaY
.
Instance methods
This interface doesn't define any specific methods, but inherits methods from its ancestors, MouseEvent
, UIEvent
, and Event
.
Specifications
Specification |
---|
UI Events # interface-wheelevent |
Browser compatibility
BCD tables only load in the browser
See also
wheel
event- Interfaces replaced by this one:
- Gecko's legacy mouse wheel event object:
MouseScrollEvent
- Gecko's legacy mouse wheel event object: