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

<p> <strong><code>Selection.extend()</code></strong> 方法移动选中区的焦点到指定的点。选中区的锚点不会移动。选中区将从锚点开始到新的焦点，不管方向。</p>

<h2 id="Syntax" name="Syntax">语法</h2>

<pre class="syntaxbox"><em>sel</em>.extend(<em>node</em>, <em>offset</em>)
</pre>

<h3 id="Parameters" name="Parameters">参数</h3>

<dl>
 <dt><em>node</em></dt>
 <dd>焦点会被移至此节点内。</dd>
 <dt><em>offset</em> {{optional_inline}}</dt>
 <dd>焦点会被移至 <code>node</code> 内的偏移位置。如果没有指定，使用 <code>0</code> 作为默认值。</dd>
</dl>

<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-extend', 'Selection.extend()')}}</td>
   <td>{{Spec2('HTML Editing')}}</td>
   <td>Initial definition</td>
  </tr>
  <tr>
   <td>{{SpecName('Selection API', '#widl-Selection-extend-void-Node-node-unsigned-long-offset', 'Selection.extend()')}}</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>Edge</th>
   <th>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari (WebKit)</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatVersionUnknown()}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown()}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatVersionUnknown()}}</td>
   <td>{{CompatVersionUnknown()}}</td>
  </tr>
  <tr>
   <td><code>offset</code> parameter is optional</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatGeckoDesktop(55)}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</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>{{CompatUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown()}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
  </tr>
  <tr>
   <td><code>offset</code> parameter is optional</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatGeckoMobile(55)}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="See_also" name="See_also">相关链接</h2>

<ul>
 <li>{{domxref("Selection")}}, 此方法所属接口。</li>
</ul>

<dl>
 <dt> </dt>
</dl>