WheelEvent.deltaY
WheelEvent.deltaY 只读属性是一个 double 类型值，声明垂直滚动量以 WheelEvent.deltaMode 为单位。
语法
var dY = event.deltaY;
例子
var syntheticEvent = new WheelEvent("syntheticWheel", {"deltaY": 4, "deltaMode": 0});
console.log(syntheticEvent.deltaY);
规范
| Specification |
|---|
| UI Events # dom-wheelevent-deltay |
浏览器兼容性
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