---
title: Set.prototype.clear()
slug: Web/JavaScript/Reference/Global_Objects/Set/clear
tags:
  - ECMAScript6
  - JavaScript
  - Prototype
  - set
  - 原型
  - 方法
translation_of: Web/JavaScript/Reference/Global_Objects/Set/clear
---
<div>{{JSRef}}</div>

<p><code><strong>clear()</strong></code> 方法用来清空一个 <code>Set</code> 对象中的所有元素。</p>

<h2 id="Syntax" name="Syntax">语法</h2>

<pre class="syntaxbox"><code><em>mySet</em>.clear();</code>
</pre>

<h3 id="返回值">返回值</h3>

<p>{{jsxref("undefined")}}.</p>

<h2 id="Examples" name="Examples">示例</h2>

<pre class="brush: js">var mySet = new Set();
mySet.add(1);
mySet.add("foo");

mySet.size;       // 2
mySet.has("foo"); // true

mySet.clear();

mySet.size;       // 0
mySet.has("bar")  // false
</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('ES6', '#sec-set.prototype.clear', 'Set.prototype.clear')}}</td>
   <td>{{Spec2('ES6')}}</td>
   <td>Initial definition.</td>
  </tr>
  <tr>
   <td>{{SpecName('ESDraft', '#sec-set.prototype.clear', 'Set.prototype.clear')}}</td>
   <td>{{Spec2('ESDraft')}}</td>
   <td> </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>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>38</td>
   <td>{{CompatGeckoDesktop("19.0")}}</td>
   <td>11</td>
   <td>25</td>
   <td>7.1</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android</th>
   <th>Chrome for Android</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>{{ CompatNo() }}</td>
   <td>25</td>
   <td>{{CompatGeckoMobile("19.0")}}</td>
   <td>{{ CompatNo() }}</td>
   <td>{{ CompatNo() }}</td>
   <td>8</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="相关链接"><strong style="font-size: 2.14285714285714rem; font-weight: 700; letter-spacing: -1px; line-height: 30px;">相关链接</strong></h2>

<ul>
 <li>{{jsxref("Set")}}</li>
 <li>{{jsxref("Set.prototype.delete()")}}</li>
</ul>