---
title: FormData.get()
slug: Web/API/FormData/get
translation_of: Web/API/FormData/get
---
<p>{{APIRef("XMLHttpRequest")}}</p>

<p>{{domxref("FormData")}}的<code><strong>get()</strong>方法用于返回FormData对象中和指定的键关联的第一个值，如果你想要返回和指定键关联的全部值，那么可以使用</code>{{domxref("FormData.getAll()","getAll()")}}方法。</p>

<div class="note">
<p><strong>注意</strong>: 该方法在<a href="/en-US/docs/Web/API/Web_Workers_API">Web Workers</a>中有效。</p>
</div>

<h2 id="语法">语法</h2>

<pre class="syntaxbox">formData.get(name);</pre>

<h3 id="append()_Parameters" name="append()_Parameters">参数</h3>

<dl>
 <dt><code>name</code></dt>
 <dd>将要获取值的键名。</dd>
</dl>

<h3 id="返回值">返回值</h3>

<p>包含值的{{domxref("FormDataEntryValue")}}。</p>

<h2 id="例子">例子</h2>

<p>下面的代码创建一个FormData对象:</p>

<pre class="brush: js">var formData = new FormData();</pre>

<p>使用{{domxref("FormData.append")}}方法添加两个数据:</p>

<pre class="brush: js">formData.append('username', 'Chris');
formData.append('username', 'Bob');</pre>

<p><code><font face="Open Sans, Arial, sans-serif">接下来使用</font>get()来回去第一个和"username"关联的值</code>:</p>

<pre class="brush: js">formData.get('username'); // Returns "Chris"</pre>

<h2 id="规范">规范</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">规范</th>
   <th scope="col">状态</th>
   <th scope="col">备注</th>
  </tr>
  <tr>
   <td>{{SpecName('XMLHttpRequest','#dom-formdata-get','get()')}}</td>
   <td>{{Spec2('XMLHttpRequest')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="浏览器兼容性">浏览器兼容性</h2>

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

<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</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatChrome(50.0)}}</td>
   <td>{{CompatGeckoDesktop('39.0')}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatNo}}</td>
  </tr>
  <tr>
   <td>Available in web workers</td>
   <td>{{CompatChrome(50.0)}}</td>
   <td>{{CompatGeckoDesktop('39.0')}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatVersionUnknown}}</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>Android Webview</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>Firefox OS (Gecko)</th>
   <th>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
   <th>Chrome for Android</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatChrome(50.0)}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatNo}}</td>
   <td>
    <p>{{CompatVersionUnknown}}</p>
   </td>
   <td>{{CompatNo}}</td>
   <td>{{CompatChrome(50.0)}}</td>
  </tr>
  <tr>
   <td>Available in web workers</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatChrome(50.0)}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatChrome(50.0)}}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="相关链接">相关链接</h2>

<ul>
 <li>{{domxref("XMLHTTPRequest")}}</li>
 <li><a href="/en-US/docs/DOM/XMLHttpRequest/Using_XMLHttpRequest" title="Using XMLHttpRequest">Using XMLHttpRequest</a></li>
 <li><a href="/en-US/docs/DOM/XMLHttpRequest/FormData/Using_FormData_Objects" title="DOM/XMLHttpRequest/FormData/Using_FormData_objects">Using FormData objects</a></li>
 <li>{{HTMLElement("Form")}}</li>
</ul>