---
title: WheelEvent.deltaY
slug: Web/API/WheelEvent/deltaY
translation_of: Web/API/WheelEvent/deltaY
---
<p>{{APIRef("DOM Events")}}</p>

<p> </p>

<p><code><strong>WheelEvent.deltaY</strong></code> 只读属性是一个 <code>double</code> 类型值, 声明垂直滚动量以<a href="https://developer.mozilla.org/zh-CN/docs/Web/API/WheelEvent/deltaMode" title="WheelEvent.deltaMode 只读属性返回一个 unsigned long 类型的值, 声明 delta 的滚动值的单位. 可能的值为:"><code>WheelEvent.deltaMode</code></a> 为单位.</p>

<h2 id="语法">语法</h2>

<pre class="syntaxbox">var <code><em>dY</em> = <em>event</em>.deltaY;</code></pre>

<h2 id="例子">例子</h2>

<pre class="brush: js">var syntheticEvent = new WheelEvent("syntheticWheel", {"deltaY": 4, "deltaMode": 0});

console.log(syntheticEvent.deltaY);
</pre>

<h2 id="规范">规范</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
  <tr>
   <td>{{SpecName('DOM3 Events','#widl-WheelEvent-deltaY','WheelEvent.deltaY')}}</td>
   <td>{{Spec2('DOM3 Events')}}</td>
   <td>Initial definition.</td>
  </tr>
 </tbody>
</table>

<h2 id="浏览器兼容性">浏览器兼容性</h2>

<p>{{ CompatibilityTable() }}</p>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Chrome</th>
   <th>Edge</th>
   <th>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari (WebKit)</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>31</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{ CompatGeckoDesktop("17.0") }}</td>
   <td>{{ CompatIE("9.0") }} [1]</td>
   <td>18</td>
   <td>9.0</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android</th>
   <th>Edge</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>IE Phone</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{ CompatVersionUnknown() }}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{ CompatGeckoMobile("17.0") }}</td>
   <td>{{ CompatUnknown() }}</td>
   <td>{{ CompatVersionUnknown() }}</td>
   <td>{{ CompatNo() }}</td>
  </tr>
 </tbody>
</table>
</div>

<p>[1] IE9 支持一个规范的一个旧版本的草稿, 这里的值的类型是 <code>long</code> 而不是一个 <code>double</code> 类型的值.</p>

<h2 class="note" id="另见">另见</h2>

<ul>
 <li>{{ event("wheel") }}</li>
 <li>{{domxref("WheelEvent")}}</li>
</ul>