---
title: history.onTitleChanged
slug: Mozilla/Add-ons/WebExtensions/API/history/onTitleChanged
tags:
  - History
translation_of: Mozilla/Add-ons/WebExtensions/API/history/onTitleChanged
---
<div>{{AddonSidebar()}}</div>

<div>当document的标题更改时触发</div>

<div> </div>

<div>你可以使用 {{WebExtAPIRef("history.onVisited")}}去进行监听. However, the {{WebExtAPIRef("history.HistoryItem")}} that this event passes to its listener does not include the page title, because the page title is typically not known at the time <code>history.onVisited</code> is sent.</div>

<div> </div>

<div>Instead, the stored {{WebExtAPIRef("history.HistoryItem")}} is updated with the page title after the page has loaded, once the title is known. The history.onTitleChanged event is fired at that time. So if you need to know the titles of pages as they are visited, listen for <code>history.onTitleChanged</code>.</div>

<h2 id="Syntax">Syntax</h2>

<pre class="syntaxbox brush:js">browser.history.onTitleChanged.addListener(listener)
browser.history.onTitleChanged.removeListener(listener)
browser.history.onTitleChanged.hasListener(listener)
</pre>

<p>Events have three functions:</p>

<dl>
 <dt><code>addListener(listener)</code></dt>
 <dd>Adds a listener to this event.</dd>
 <dt><code>removeListener(listener)</code></dt>
 <dd>Stop listening to this event. The <code>listener</code> argument is the listener to remove.</dd>
 <dt><code>hasListener(listener)</code></dt>
 <dd>Check whether <code>listener</code> is registered for this event. Returns <code>true</code> if it is listening, <code>false</code> otherwise.</dd>
</dl>

<h2 id="addListener_syntax">addListener syntax</h2>

<h3 id="Parameters">Parameters</h3>

<dl>
 <dt><code>callback</code></dt>
 <dd>
 <p>Function that will be called when this event occurs. The function will be passed an object with the following properties:</p>

 <dl class="reference-values">
  <dt><code>url</code></dt>
  <dd><code>String</code>. URL of the page visited.</dd>
  <dt><code>title</code></dt>
  <dd><code>String</code>. Title of the page visited.</dd>
 </dl>
 </dd>
</dl>

<h2 id="Browser_compatibility">Browser compatibility</h2>

<p class="hidden">The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out <a href="https://github.com/mdn/browser-compat-data">https://github.com/mdn/browser-compat-data</a> and send us a pull request.</p>

<p>{{Compat("webextensions.api.history.onTitleChanged")}}</p>

<h2 id="Examples">Examples</h2>

<p>Listen for title change events, and log the URL and title of the visited pages.</p>

<pre class="brush: js">function handleTitleChanged(item) {
  console.log(item.title);
  console.log(item.url);
}

browser.history.onTitleChanged.addListener(handleTitleChanged);</pre>

<p>{{WebExtExamples}}</p>

<div class="note"><strong>Acknowledgements</strong>

<p>This API is based on Chromium's <a href="https://developer.chrome.com/extensions/history#event-onVisited"><code>chrome.history</code></a> API. This documentation is derived from <a href="https://chromium.googlesource.com/chromium/src/+/master/chrome/common/extensions/api/history.json"><code>history.json</code></a> in the Chromium code.</p>

<p>Microsoft Edge compatibility data is supplied by Microsoft Corporation and is included here under the Creative Commons Attribution 3.0 United States License.</p>
</div>

<div class="hidden">
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