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

<p>The <strong><code>Selection.rangeCount</code></strong>是一个返回选区(selection)中range对象数量的只读属性。</p>

<p>在网页使用者点击一个加载完毕的新打开的页面之前，<strong>rangeCount</strong><font face="Consolas, Liberation Mono, Courier, monospace">的值是0</font>。在使用者点击页面之后，<font face="Consolas, Liberation Mono, Courier, monospace">rangeCount的值变为1，即使并没有可视的选区(selection)。</font></p>

<p>使用者一般情况下在一次只能选择一个range ，所以通常情况下<strong>rangeCount属性</strong>的值总为1。脚本(如javascript)可以使选区包含多个range。</p>

<p>Gecko 浏览器允许跨表格单元格获得多个选区(此处可能翻译不准). Firefox allows to select multiple ranges in the document by using Ctrl+click (unless the click within an element with display: table-cell).</p>

<h2 id="Syntax" name="Syntax">用法</h2>

<pre class="syntaxbox"><em>value</em> =<em> sel</em>.rangeCount
</pre>

<h2 id="例子">例子</h2>

<p>下面这个例子会每隔一秒显示一次rangeCount的值。在浏览器中选择文本，然后看看他的改变。</p>

<h3 id="HTML_Content">HTML Content</h3>

<pre class="brush: html">//打开控制台看看selection中有多少range对象。
//在Gecko浏览器，当你用鼠标在表格单元格中拖动的同时按住Ctrl，你可以选择多个range。

&lt;table&gt;
&lt;tr&gt;&lt;td&gt;a.1&lt;td&gt;a.2
&lt;tr&gt;&lt;td&gt;b.1&lt;td&gt;b.2


</pre>

<h3 id="JavaScript_Content">JavaScript Content</h3>

<pre class="brush: js">window.setInterval(function () {
  console.log(window.getSelection().rangeCount);
}, 1000);
</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-rangecount', 'Selection.rangeCount')}}</td>
   <td>{{Spec2('HTML Editing')}}</td>
   <td>Initial definition</td>
  </tr>
  <tr>
   <td>{{SpecName('Selection API', '#widl-Selection-rangeCount', 'Selection.rangeCount')}}</td>
   <td>{{Spec2('Selection API')}}</td>
   <td>Current</td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility" name="Browser_compatibility">Browser compatibility</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>{{CompatVersionUnknown()}}</td>
   <td>{{CompatVersionUnknown()}}</td>
   <td>{{CompatVersionUnknown()}}</td>
   <td>{{CompatVersionUnknown()}}</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">See also</h2>

<ul>
 <li>{{domxref("Selection")}}, the interface it belongs to.</li>
</ul>