WheelEvent.deltaMode
  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. | 
Syntax
var unit = event.deltaMode;
Example
var syntheticEvent = new WheelEvent("syntheticWheel", {"deltaX": 4, "deltaMode": 0});
console.log(syntheticEvent.deltaMode);
Specifications
| Specification | 
|---|
| UI Events # dom-wheelevent-deltamode | 
Browser compatibility
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