---
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></code>方法會返回 <code>FormData 物件中，</code>指定 key 值所對應之第一組物件中的 value 值 。然而，如果您想要獲得多組以及全部的 value ，那應該使用 {{domxref("FormData.getAll()","getAll()")}} 方法。</p>

<p><strong>注意</strong>:  這個方法已可以在 <a href="/en-US/docs/Web/API/Web_Workers_API">Web Workers</a> 中使用。</p>

<h2 id="語法">語法</h2>

<pre>formData.get(name);</pre>

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

<dl>
 <dt><code>name</code></dt>
 <dd>一個 {{domxref("USVString")}} ，代表您想要得到的 value 所對應的 key 值名稱。</dd>
</dl>

<h3 id="回傳值">回傳值</h3>

<p>A {{domxref("FormDataEntryValue")}} containing the value.</p>

<h2 id="範例">範例</h2>

<p>下面一行程式會產生一個空的 <code>FormData 物件：</code></p>

<pre>var formData = new FormData();</pre>

<p>用 {{domxref("FormData.append")}} 方法新增兩組 <code>username 值</code></p>

<pre>formData.append('username', 'Chris');
formData.append('username', 'Bob');</pre>

<p>接下來使用 <code>get() 方法，將只會返回上一步驟，第一組新增的 username 所對應的值</code></p>

<pre>formData.get('username'); // Returns "Chris"</pre>

<h2 id="規範">規範</h2>

<table>
 <tbody>
  <tr>
   <th scope="col">規範</th>
   <th scope="col">狀態</th>
   <th scope="col">註解</th>
  </tr>
  <tr>
   <td>{{SpecName('XMLHttpRequest','#dom-formdata-get','get()')}}</td>
   <td>{{Spec2('XMLHttpRequest')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="瀏覽器相容性">瀏覽器相容性</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="sect1"> </h2>

<h2 id="延伸閱讀">延伸閱讀</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>