---
title: Body.blob()
slug: Web/API/Body/blob
tags:
  - Body.blob()
translation_of: Web/API/Body/blob
---
<p>{{APIRef("Fetch")}}</p>

<p>{{domxref("Body")}}  mixin的 <strong><code>blob()</code></strong>方法使用一个 {{domxref("Response")}} 流，并将其读取完成。它返回一个使用{{domxref("Blob")}}解决的promise。</p>

<h2 id="句法">句法</h2>

<pre class="brush: js">response.blob().then(function(myBlob) {
  // do something with myBlob
});</pre>

<h3 id="参数">参数</h3>

<p>None.</p>

<h3 id="返回值">返回值</h3>

<p>A promise that resolves with a {{domxref("Blob")}}.</p>

<h2 id="例子">例子</h2>

<p>在我们 <a href="https://github.com/mdn/fetch-examples/tree/gh-pages/fetch-request">fetch request example</a> (run <a href="http://mdn.github.io/fetch-examples/fetch-request/">fetch request live</a>)中，我们使用<a href="/zh-CN/docs/Mozilla/Add-ons/WebExtensions/API/webRequest/RequestFilter">Request.Request</a>构造方法创建了一个新的request对象，然后使用它来获取一个JPG文件。当fetch成功的时候，我们使用blob()从response中读取一个<a href="/zh-CN/docs/Web/API/Blob">Blob</a>对象，并使用<a href="/zh-CN/docs/Web/API/URL/createObjectURL">URL.createObjectURL</a> 将它放入一个object URL ，然后把URL设置为<a href="/zh-CN/docs/Web/HTML/Element/img">img</a>元素的src属性以显示这张图片。</p>

<p> </p>

<pre class="brush: js">var myImage = document.querySelector('img');

var myRequest = new Request('flowers.jpg');

fetch(myRequest)
.then(function(response) {
  return response.blob();
})
.then(function(myBlob) {
  var objectURL = URL.createObjectURL(myBlob);
  myImage.src = objectURL;
});
</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">说明</th>
  </tr>
  <tr>
   <td>{{SpecName('Fetch','#dom-body-blob','blob()')}}</td>
   <td>{{Spec2('Fetch')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="浏览器兼容性">浏览器兼容性</h2>

<p>{{ CompatibilityTable}}</p>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Chrome</th>
   <th>Edge</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) }} [1]<br>
     </td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{ CompatGeckoDesktop(39)}} [2]</td>
   <td>{{ CompatNo }}</td>
   <td>
    <p>29 [3]</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>Edge</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>{{CompatVersionUnknown}}</td>
   <td>{{ CompatNo }}</td>
   <td>{{ CompatNo }}</td>
   <td>{{ CompatNo }}</td>
   <td>{{ CompatNo }}</td>
   <td>{{ CompatNo }}</td>
   <td>{{ CompatNo }}</td>
  </tr>
 </tbody>
</table>
</div>

<p>[1] Behind a preference in version 41.</p>

<p>[2] Behind a preference starting with version 34.</p>

<p>[3] Behind a preference in version 28.</p>

<h2 id="另见">另见</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>