---
title: Selection.anchorOffset
slug: Web/API/Selection/anchorOffset
translation_of: Web/API/Selection/anchorOffset
---
<div>
<div>{{ ApiRef("DOM") }}{{SeeCompatTable}}</div>
</div>

<p>只读属性，返回选区的锚节点（ {{domxref("Selection.anchorNode")}}）起点偏移量的数字。返回值从零开始计数，如果选区从锚节点（{{domxref("Selection.anchorNode")}}）的第一个字符开始，返回值为0。</p>

<h2 id="Syntax" name="Syntax">语法</h2>

<pre class="syntaxbox"><em>number</em> =<em> sel</em>.anchorOffset</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('HTML Editing', '#dom-selection-anchoroffset', 'Selection.anchorOffset')}}</td>
   <td>{{Spec2('HTML Editing')}}</td>
   <td>Initial definition</td>
  </tr>
  <tr>
   <td>{{SpecName('Selection API', '#widl-Selection-anchorOffset', 'Selection.anchorOffset')}}</td>
   <td>{{Spec2('Selection API')}}</td>
   <td>Current</td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility" name="Browser_compatibility">浏览器兼容性</h2>

<div>{{CompatibilityTable}}</div>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Chrome</th>
   <th>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari (WebKit)</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatVersionUnknown()}}</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</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>Firefox OS</th>
   <th>IE Phone</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatVersionUnknown()}}</td>
   <td>1.0</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("Selection")}}, the interface it belongs to.</li>
</ul>