---
title: Storage.getItem()
slug: Web/API/Storage/getItem
translation_of: Web/API/Storage/getItem
---
<p>{{APIRef("Web Storage API")}}</p>

<p><code>getItem()</code> 作为 {{domxref("Storage")}} 接口的方法，接受一个键名（key name）作为参数，并返回对应键名的值（key's value）。</p>

<h2 id="语法">语法</h2>

<pre class="syntaxbox">var <em>aValue</em> = <em>storage</em>.getItem(<em>keyName</em>);
</pre>

<h3 id="参数">参数</h3>

<dl>
 <dt><em><code>keyName</code></em></dt>
 <dd>一个包含键名的 {{domxref("DOMString")}}。</dd>
</dl>

<h3 id="返回值">返回值</h3>

<p>一个 {{domxref("DOMString")}}，键名对应的值。如果键名不存在于存储中，则返回 <code>null</code>。</p>

<h2 id="示例">示例</h2>

<p>下面的函数从本地存储中获取三个数据项，然后使用他们在页面上设置自定义样式：</p>

<pre class="brush: js">function setStyles() {
  var currentColor = localStorage.getItem('bgcolor');
  var currentFont = localStorage.getItem('font');
  var currentImage = localStorage.getItem('image');

  document.getElementById('bgcolor').value = currentColor;
  document.getElementById('font').value = currentFont;
  document.getElementById('image').value = currentImage;

  htmlElem.style.backgroundColor = '#' + currentColor;
  pElem.style.fontFamily = currentFont;
  imgElem.setAttribute('src', currentImage);
}</pre>

<div class="note">
<p><strong>备注：</strong>一个实际的例子 <a href="https://github.com/mdn/web-storage-demo">Web Storage Demo</a>。</p>
</div>

<h2 id="规范">规范</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('Web Storage', '#dom-storage-getitem', 'getItem()')}}</td>
   <td>{{Spec2('Web Storage')}}</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>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari (WebKit)</th>
  </tr>
  <tr>
   <td>localStorage</td>
   <td>4</td>
   <td>3.5</td>
   <td>8</td>
   <td>10.50</td>
   <td>4</td>
  </tr>
  <tr>
   <td>sessionStorage</td>
   <td>5</td>
   <td>2</td>
   <td>8</td>
   <td>10.50</td>
   <td>4</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>IE Phone</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>2.1</td>
   <td>{{ CompatUnknown }}</td>
   <td>8</td>
   <td>11</td>
   <td>iOS 3.2</td>
  </tr>
 </tbody>
</table>
</div>

<p>各浏览器支持的 localStorage 和 sessionStorage 容量不同。测试页面：<a class="external" href="http://dev-test.nemikor.com/web-storage/support-test/" title="http://dev-test.nemikor.com/web-storage/support-test/">detailed rundown of all the storage capacities for various browsers</a>。</p>

<div class="note">
<p><strong>Note: </strong>since iOS 5.1, Safari Mobile stores localStorage data in the cache folder, which is subject to occasional clean up, at the behest of the OS, typically if space is short.</p>
</div>

<h2 id="相关链接">相关链接</h2>

<p><a href="/zh-CN/docs/Web/API/Web_Storage_API/Using_the_Web_Storage_API">使用 Web Storage API</a></p>