function WheelEvent(ev) {
    // [Constructor(DOMString typeArg, optional WheelEventInit wheelEventInitDict)]
    // interface WheelEvent : MouseEvent {
    //     // DeltaModeCode
    //     const unsigned long DOM_DELTA_PIXEL = 0x00;
    //     const unsigned long DOM_DELTA_LINE = 0x01;
    //     const unsigned long DOM_DELTA_PAGE = 0x02;
    //     readonly    attribute double        deltaX;
    //     readonly    attribute double        deltaY;
    //     readonly    attribute double        deltaZ;
    //     readonly    attribute unsigned long deltaMode;
    // };

    MouseEvent.call(this, ev);

    /**
     * @name WheelEvent#DOM_DELTA_PIXEL
     * @type Number
     */
    this.DOM_DELTA_PIXEL = 0x00;

    /**
     * @name WheelEvent#DOM_DELTA_LINE
     * @type Number
     */
    this.DOM_DELTA_LINE = 0x01;

    /**
     * @name WheelEvent#DOM_DELTA_PAGE
     * @type Number
     */
    this.DOM_DELTA_PAGE = 0x02;

    /**
     * @name WheelEvent#deltaX
     * @type Number
     */
    this.deltaX = ev.deltaX;

    /**
     * @name WheelEvent#deltaY
     * @type Number
     */
    this.deltaY = ev.deltaY;

    /**
     * @name WheelEvent#deltaZ
     * @type Number
     */
    this.deltaZ = ev.deltaZ;

    /**
     * @name WheelEvent#deltaMode
     * @type Number
     */
    this.deltaMode = ev.deltaMode;
}
See [UI Events (formerly DOM Level 3 Events)](http://www.w3.org/TR/2015/WD-uievents-20150428/#events-wheelevents).

@class WheelEvent
@augments UIEvent

@param {Event} ev The native DOM event.