The WheelEvent.deltaMode read-only property 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.


var unit = event.deltaMode;


var syntheticEvent = new WheelEvent("syntheticWheel", {"deltaX": 4, "deltaMode": 0});



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

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 31 (Yes) 17.0 (17.0) 9.0 18 7.0
Feature Android Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support (Yes) 17.0 (17.0) ? (Yes) Not supported

See also

Document Tags and Contributors

 Contributors to this page: m_gol, jwhitlock, teoli
 Last updated by: m_gol,