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.

Not to be confused with a scroll event: Please keep in mind that the default action of a wheel event is implementation-defined — a wheel event doesn't necessarily dispatch a scroll event. Even if it does, that doesn't mean that the delta values in the wheel event must reflect the content's scrolling direction. So do not rely on delta properties to get the content's scrolling direction — instead detect value changes of scrollLeft and scrollTop in a scroll event.

Constructor

WheelEvent()
Creates a WheelEvent object.

Properties

This interface inherits properties from its parents, 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 the delta values scroll amount. Permitted values are:
Constant Value Description
DOM_DELTA_PIXEL 0x00 The delta values are specified in pixels.
DOM_DELTA_LINE 0x01 The delta values are specified in lines.
DOM_DELTA_PAGE 0x02 The delta values are specified in pages.

Methods

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

Specifications

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

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support31 Yes17918 Yes
Pinch-to-zoom maps to WheelEvent + ctrl key.31 ?55 ? ? Yes
WheelEvent() constructor Yes Yes17 No Yes Yes
deltaMode31 Yes17918 Yes
deltaX31 Yes179118 Yes
deltaY31 Yes179118 Yes
deltaZ31 Yes179118 Yes
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes Yes17 Yes ? ?
Pinch-to-zoom maps to WheelEvent + ctrl key. Yes Yes ?55 ? ? ?
WheelEvent() constructor Yes Yes Yes17 Yes ? ?
deltaMode Yes Yes Yes17 Yes ? ?
deltaX Yes Yes Yes17 Yes ? ?
deltaY Yes Yes Yes17 Yes ? ?
deltaZ Yes Yes Yes17 Yes ? ?

1. IE9 supports an old draft of the spec where this value was a long instead of a double.

See also

Document Tags and Contributors

Last updated by: fscholz,