WheelEvent: deltaMode property

The WheelEvent.deltaMode read-only property returns an unsigned long representing the unit of the delta values scroll amount. Permitted values are:

You must check the deltaMode property to determine the unit of the deltaX, deltaY, and deltaZ values. Do not assume that those values are specified in pixels. Some browsers, for compatibility reasons, may return different units for the delta* values depending on whether deltaMode has been accessed, to accommodate for websites not explicitly checking the deltaMode property.

Value

An unsigned long.

Examples

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

console.log(syntheticEvent.deltaMode);

Specifications

Browser compatibility

See also

• wheel
• WheelEvent