---
title: Set.prototype.clear()
slug: Web/JavaScript/Reference/Global_Objects/Set/clear
tags:
  - ECMAScript 2015
  - JavaScript
  - 原型
  - 參考
  - 方法
  - 集合
translation_of: Web/JavaScript/Reference/Global_Objects/Set/clear
---
<div>{{JSRef}}</div>

<p><code><strong>clear()</strong></code> 方法會從一個 <code>Set</code> 物件中移除其所有元素。</p>

<div>{{EmbedInteractiveExample("pages/js/set-prototype-clear.html")}}</div>



<h2 id="語法">語法</h2>

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

<h3 id="回傳值">回傳值</h3>

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

<h2 id="範例">範例</h2>

<h3 id="使用_clear_方法">使用 <code>clear</code> 方法</h3>

<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="規範">規範</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">規範</th>
   <th scope="col">狀態</th>
   <th scope="col">註</th>
  </tr>
  <tr>
   <td>{{SpecName('ES2015', '#sec-set.prototype.clear', 'Set.prototype.clear')}}</td>
   <td>{{Spec2('ES2015')}}</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="瀏覽器相容性">瀏覽器相容性</h2>



<p>{{Compat("javascript.builtins.Set.clear")}}</p>

<h2 id="另見">另見</h2>

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