---
title: Document.defaultView
slug: Web/API/Document/defaultView
translation_of: Web/API/Document/defaultView
---
<div>{{ApiRef}}</div>

<p>在瀏覽器中，<strong><code>document.defaultView</code></strong> 屬性會指向一個目前 {{Glossary("Browsing_context", "document")}} 所屬的 {{domxref("Window", "window")}} 物件，若無則為 <code>null</code>。</p>

<h2 id="語法">語法</h2>

<pre class="syntaxbox">var <var>win</var> = document.defaultView;</pre>

<p>此為唯讀屬性。</p>

<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('HTML WHATWG', '#dom-document-defaultview', 'Document.defaultView')}}</td>
   <td>{{Spec2('HTML WHATWG')}}</td>
   <td>No change</td>
  </tr>
  <tr>
   <td>{{SpecName('HTML5 W3C', 'browsers.html#dom-document-defaultview', 'Document.defaultView')}}</td>
   <td>{{Spec2('HTML5 W3C')}}</td>
   <td>Initial definition</td>
  </tr>
 </tbody>
</table>

<h2 id="瀏覽器相容性">瀏覽器相容性</h2>

<div>{{CompatibilityTable}}</div>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Firefox (Gecko)</th>
   <th>Chrome</th>
   <th>Edge</th>
   <th>Internet Explorer</th>
   <th>Edge</th>
   <th>Opera</th>
   <th>Safari</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatIE("9.0")}}</td>
   <td>0.10</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>Firefox Mobile (Gecko)</th>
   <th>Android</th>
   <th>Edge</th>
   <th>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>