---
title: Headers.getAll()
slug: Web/API/Headers/getAll
translation_of: Web/API/Headers/getAll
---
<p>{{APIRef("Fetch")}}{{ SeeCompatTable() }}</p>

<p><strong><code>getAll()</code></strong> 方法会以数组形式返回指定header的所有值. 如果指定的header未存在,则返回一个空数组.</p>

<div class="note">
<p><strong>Note:</strong>出于安全原因, 部分头信息只能被用户代理控制. 这些头信息包括 {{Glossary("Forbidden_header_name", "forbidden header names", 1)}}  和 {{Glossary("Forbidden_response_header_name", "forbidden response header names", 1)}}.</p>
</div>

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

<pre class="brush: js">myHeaders.getAll(name);</pre>

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

<dl>
 <dt><em>name</em></dt>
 <dd>需检索的HTTP header名称. 如果HTTP header中不存在指定名称<span style="line-height: 19.0909080505371px;">则抛出一个 </span><span style="line-height: 19.0909080505371px;">{{jsxref("TypeError")}}.</span></dd>
</dl>

<h3 id="Returns">Returns</h3>

<p>An {{domxref("Array")}} containing a {{domxref("ByteString")}} sequence representing the values of the retrieved header.</p>

<h2 id="Example">Example</h2>

<p>Creating an empty <code>Headers</code> object is simple:</p>

<pre class="brush: js">var myHeaders = new Headers(); // Currently empty</pre>

<p>You could add a header to this using {{domxref("Headers.append")}}, then retrieve it using <code>getAll()</code>:</p>

<pre class="brush: js">myHeaders.append('Content-Type', 'image/jpeg');
myHeaders.getAll('Content-Type'); // Returns [ "image/jpeg" ]
</pre>

<p>If the header has multiple values associated with it, the array will contain all the values, in the order they were added to the Headers object:</p>

<pre class="brush: js">myHeaders.append('Accept-Encoding', 'deflate');
myHeaders.append('Accept-Encoding', 'gzip');
myHeaders.getAll('Accept-Encoding'); // Returns [ "deflate", "gzip" ]</pre>

<div class="note">
<p><strong>Note</strong>: Use {{domxref("Headers.get")}} to return only the first value added to the <code>Headers</code> object.</p>
</div>

<h2 id="Specifications">Specifications</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
  <tr>
   <td>{{SpecName('Fetch','#dom-headers-getall','getAll()')}}</td>
   <td>{{Spec2('Fetch')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Browser compatibility</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 (WebKit)</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{ CompatChrome(42) }}<br>
    {{ CompatChrome(41) }} behind pref<br>
     </td>
   <td>{{ CompatGeckoDesktop(39)}}<br>
    34 behind pref</td>
   <td>{{ CompatNo }}</td>
   <td>
    <p>29<br>
     28 behind pref</p>
   </td>
   <td>{{ CompatNo }}</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>Firefox OS (Gecko)</th>
   <th>IE Phone</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
   <th>Chrome for Android</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{ CompatNo }}</td>
   <td>{{ CompatNo }}</td>
   <td>{{ CompatNo }}</td>
   <td>{{ CompatNo }}</td>
   <td>{{ CompatNo }}</td>
   <td>{{ CompatNo }}</td>
   <td>{{ CompatNo }}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="See_also">See also</h2>

<ul>
 <li><a href="/en-US/docs/Web/API/ServiceWorker_API">ServiceWorker API</a></li>
 <li><a href="/en-US/docs/Web/HTTP/Access_control_CORS">HTTP access control (CORS)</a></li>
 <li><a href="/en-US/docs/Web/HTTP">HTTP</a></li>
</ul>