files/zh-cn/web/api/response/bodyused/index.html


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79

---
title: Response.bodyUsed
slug: Web/API/Response/bodyUsed
translation_of: Web/API/Response/bodyUsed
tags:
  - API
  - Fetch
  - Property
  - Reference
  - bodyUsed
  - Response
browser-compat: api.Response.bodyUsed
---
<p>{{APIRef("Fetch")}}{{ SeeCompatTable }}</p>

<p><strong><code>bodyUsed</code></strong><code> 是</code>{{domxref("Response")}} mixin中的一个<code>只读属性。用以表示该body是否被使用过。</code></p>

<h2 id="语法">语法</h2>

<pre class="brush: js">var myBodyUsed = response.bodyUsed;</pre>

<h3 id="可能的值">可能的值</h3>

<p>{{domxref("Boolean")}}.</p>

<h2 id="示例">示例</h2>

<p>在以下<a href="https://github.com/mdn/fetch-examples/tree/gh-pages/fetch-request">fetch 请求示例</a>（运行 <a href="http://mdn.github.io/fetch-examples/fetch-request/">fetch request live</a>）。通过{{domxref("Request.Request")}}构造器创建了一个fetch请求，来获得一张JPG图片。当fetch成功后，通过{{domxref("Blob")}} 来使用了fetch返回的资源--{{domxref("URL.createObjectURL")}}创建该资源的URL，并作为 {{htmlelement("img")}}元素的src源来显示图片。</p>

<p>注意：<code>在response.blob()被调用前后，</code>输出<code>response.bodyUsed的差异。</code></p>

<h3 id="HTML_Content">HTML Content</h3>

<pre class="brush: html">&lt;img class="my-image" src="https://wikipedia.org/static/images/project-logos/frwiki-1.5x.png"&gt;
</pre>

<h3 id="JS_Content">JS Content</h3>

<pre class="brush: js">var myImage = document.querySelector('.my-image');
fetch('https://upload.wikimedia.org/wikipedia/commons/7/77/Delete_key1.jpg').then(function(response) {
    console.log(response.bodyUsed);
    var res = response.blob();
    console.log(response.bodyUsed);
    return res;
}).then(function(response) {
    var objectURL = URL.createObjectURL(response);
    myImage.src = objectURL;
});</pre>

<p>{{ EmbedLiveSample('Example', '100%', '250px') }}</p>

<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-body-bodyused','bodyUsed')}}</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>

{{Compat("api.Response.bodyUsed")}}

<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>