---
title: MouseEvent.offsetY
slug: Web/API/MouseEvent/offsetY
tags:
  - API
  - 只读属性
  - 鼠标事件
translation_of: Web/API/MouseEvent/offsetY
---
<p>{{APIRef("DOM Events")}}{{SeeCompatTable}}</p>

<p>MouseEvent 接口的只读属性 <strong>offsetY </strong>规定了事件对象与目标节点的内填充边（padding edge）在 Y 轴方向上的偏移量。</p>

<h2 id="语法">语法</h2>

<pre class="syntaxbox">var yOffset = <em>instanceOfMouseEvent</em>.offsetY;
</pre>

<h3 id="返回值">返回值</h3>

<p>一个<code>双精度</code> 浮点值。早期的规范将其规定为整数值。详见浏览器兼容性部分。</p>

<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('CSSOM View', '#dom-mouseevent-offsety', 'MouseEvent')}}</td>
   <td>{{Spec2('CSSOM View')}}</td>
   <td>Initial definition</td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility" name="Browser_compatibility">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</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatGeckoDesktop("39.0")}}</td>
   <td>6</td>
   <td>{{ CompatVersionUnknown() }}</td>
   <td>{{ CompatVersionUnknown() }}</td>
  </tr>
  <tr>
   <td>Redefined from <code>long</code> to <code>double</code></td>
   <td>{{CompatChrome(56)}}</td>
   <td>{{ CompatUnknown() }}</td>
   <td>{{ CompatUnknown() }}</td>
   <td>{{ CompatUnknown() }}</td>
   <td>{{ CompatUnknown() }}</td>
   <td>{{ CompatUnknown() }}</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android Webview</th>
   <th>Chrome for Android</th>
   <th>Edge</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatGeckoMobile("43.0")}}</td>
   <td>{{ CompatUnknown() }}</td>
   <td>{{ CompatUnknown() }}</td>
   <td>{{ CompatUnknown() }}</td>
  </tr>
  <tr>
   <td>Redefined from <code>long</code> to <code>double</code></td>
   <td>{{CompatChrome(56)}}</td>
   <td>{{CompatChrome(56)}}</td>
   <td>{{ CompatUnknown() }}</td>
   <td>{{ CompatUnknown() }}</td>
   <td>{{ CompatUnknown() }}</td>
   <td>{{ CompatUnknown() }}</td>
   <td>{{ CompatUnknown() }}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="See_also" name="See_also">相关内容</h2>

<ul>
 <li>{{ domxref("MouseEvent") }}</li>
</ul>