---
title: Event.defaultPrevented
slug: Web/API/Event/defaultPrevented
translation_of: Web/API/Event/defaultPrevented
---
<div>{{ APIRef("DOM") }}</div>

<h2 id="概述">概述</h2>

<p>回傳一個布林值，表示事件的預設行為是否被取消，也就是事件物件是否曾執行 {{domxref("event.preventDefault()", "preventDefault()")}} 方法。</p>

<div class="note"><strong>註：</strong>You should use this instead of the non-standard, deprecated<code> getPreventDefault()</code> method (see {{ bug(691151) }}).</div>

<h2 id="語法">語法</h2>

<pre class="eval">bool = event.defaultPrevented </pre>

<h2 id="範例">範例</h2>

<pre> if (e.defaultPrevented) {
   /* the default was prevented */
 }
</pre>

<h2 id="規範">規範</h2>

<table class="standard-table">
 <thead>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
 </thead>
 <tbody>
  <tr>
   <td>{{SpecName('DOM WHATWG', '#dom-event-defaultprevented', 'Event.defaultPrevented()')}}</td>
   <td>{{ Spec2('DOM WHATWG') }}</td>
   <td> </td>
  </tr>
  <tr>
   <td>{{SpecName('DOM4', '#dom-event-defaultprevented', 'Event.defaultPrevented')}}</td>
   <td>{{Spec2('DOM4')}}</td>
   <td>Initial definition.</td>
  </tr>
 </tbody>
</table>

<h2 id="瀏覽器相容性"><span style="font-size: 1.71428571428571rem; letter-spacing: -0.021em; line-height: 1;">瀏覽器相容性</span></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>{{ CompatChrome(18) }}</td>
   <td>{{ CompatGeckoDesktop("6.0") }}</td>
   <td>{{ CompatIE(9.0) }}</td>
   <td>{{ CompatOpera(11.0) }}</td>
   <td>{{ CompatSafari("5.0") }}</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>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{ CompatUnknown() }}</td>
   <td>{{ CompatGeckoMobile("6.0") }}</td>
   <td>{{ CompatUnknown() }}</td>
   <td>{{ CompatUnknown() }}</td>
   <td>{{ CompatSafari(5.0) }}</td>
  </tr>
 </tbody>
</table>
</div>

<ul>
</ul>