---
title: Window.top
slug: Web/API/Window/top
tags:
  - API
  - HTML DOM
  - Property
  - Reference
  - Window
translation_of: Web/API/Window/top
---
<p>{{APIRef}}</p>

<p>返回窗口层级最顶层窗口的引用。</p>

<h2 id="语法" name="语法">语法</h2>

<pre class="eval">var <em>topWindow</em> = window.top;
</pre>

<h2 id="备注" name="备注"><span style="font-family: Arial,Arial,Helvetica,sans-serif; line-height: 20px;">备注</span></h2>

<p> <code style="font-style: normal; line-height: 1.5;"><a href="https://developer.mozilla.org/zh-CN/DOM/window.parent" title="en/DOM/window.parent">window.parent</a></code> <span style="line-height: 1.5;">返回当前窗口的直接父对象，而 </span>{{domxref("window.top")}}<span style="line-height: 1.5;"> </span><span style="font-family: 'Courier New','Andale Mono',monospace; line-height: inherit;">返回最顶层的窗口对象。</span></p>

<p> </p>

<p>当你在处理父窗口的子框架（subframe），而你想获取顶层框架时，这个属性相当有用。</p>

<h2 id="规范" name="规范" style="line-height: 24px;">规范</h2>

<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', 'browsers.html#dom-top', 'window.top')}}</td>
   <td>{{Spec2('HTML WHATWG')}}</td>
   <td> </td>
  </tr>
  <tr>
   <td>{{SpecName('HTML5 W3C', 'browsers.html#dom-top', 'window.top')}}</td>
   <td>{{Spec2('HTML5 W3C')}}</td>
   <td>Initial definition</td>
  </tr>
 </tbody>
</table>

<h2 id="浏览器兼容性" name="浏览器兼容性">浏览器兼容性</h2>

<p>{{Compat("api.Window.top")}}</p>