--- 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>