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<article id="wikiArticle">
<p id="sect1"></p><p></p>
<p><code><strong>set()</strong></code> 方法为 <code>Map</code> 对象添加或更新一个指定了键(<code>key</code>)和值(<code>value</code>)的(新)键值对。</p>
<div><iframe class="interactive interactive-js" frameborder="0" height="250" src="https://interactive-examples.mdn.mozilla.net/pages/js/map-prototype-set.html" width="100%"></iframe></div>
<p class="hidden">The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone <a class="external" href="https://github.com/mdn/interactive-examples" rel="noopener">https://github.com/mdn/interactive-examples</a> and send us a pull request.</p>
<h2 id="语法">语法</h2>
<pre><code class="language-javascript"><code><em>myMap</em>.set(key, value);</code></code></pre>
<h3 id="参数">参数</h3>
<dl>
<dt>key</dt>
<dd>要添加至相应 <code>Map</code> 对象的元素的键。</dd>
<dt>value</dt>
<dd>要添加至相应 <code>Map</code> 对象的元素的值。</dd>
</dl>
<h3 id="返回值">返回值</h3>
<p><code>Map</code> 对象</p>
<h2 id="示例">示例</h2>
<h3 id="使用_set_方法">使用 <code>set</code> 方法</h3>
<pre><code class="language-javascript">var myMap = new Map();
// 将一个新元素添加到 Map 对象
myMap.set("bar", "foo");
myMap.set(1, "foobar");
// 在Map对象中更新某个元素的值
myMap.set("bar", "baz");
</code></pre>
<h3 id="Using_the_set_method_with_chaining">Using the <code>set</code> method with chaining</h3>
<p>因为 Set() 方法返回 Map 对象本身,所以你可以像下面这样链式调用它:</p>
<pre><code class="language-javascript">// Add new elements to the map with chaining.
myMap.set('bar', 'foo')
.set(1, 'foobar')
.set(2, 'baz');
</code></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><a class="external" href="https://www.ecma-international.org/ecma-262/6.0/#sec-map.prototype.set" hreflang="en" lang="en" rel="noopener">ECMAScript 2015 (6th Edition, ECMA-262)<br/><small lang="zh-CN">Map.prototype.set</small></a></td>
<td><span class="spec-Standard">Standard</span></td>
<td>Initial definition.</td>
</tr>
<tr>
<td><a class="external" href="https://tc39.github.io/ecma262/#sec-map.prototype.set" hreflang="en" lang="en" rel="noopener">ECMAScript Latest Draft (ECMA-262)<br/><small lang="zh-CN">Map.prototype.set</small></a></td>
<td><span class="spec-Draft">Draft</span></td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容性">浏览器兼容性</h2>
<div class="hidden">The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out <a class="external" href="https://github.com/mdn/browser-compat-data" rel="noopener">https://github.com/mdn/browser-compat-data</a> and send us a pull request.</div>
<p></p><div class="bc-data"><a class="bc-github-link external" href="https://github.com/mdn/browser-compat-data" rel="noopener">Update compatibility data on GitHub</a><table class="bc-table bc-table-js"><thead><tr class="bc-platforms"><td></td><th class="bc-platform-desktop" colspan="6"><span>Desktop</span></th><th class="bc-platform-mobile" colspan="7"><span>Mobile</span></th><th class="bc-platform-server" colspan="1"><span>Server</span></th></tr><tr class="bc-browsers"><td></td><th class="bc-browser-chrome"><span class="bc-head-txt-label bc-head-icon-chrome">Chrome</span></th><th class="bc-browser-edge"><span class="bc-head-txt-label bc-head-icon-edge">Edge</span></th><th class="bc-browser-firefox"><span class="bc-head-txt-label bc-head-icon-firefox">Firefox</span></th><th class="bc-browser-ie"><span class="bc-head-txt-label bc-head-icon-ie">Internet Explorer</span></th><th class="bc-browser-opera"><span class="bc-head-txt-label bc-head-icon-opera">Opera</span></th><th class="bc-browser-safari"><span class="bc-head-txt-label bc-head-icon-safari">Safari</span></th><th class="bc-browser-webview_android"><span class="bc-head-txt-label bc-head-icon-webview_android">Android webview</span></th><th class="bc-browser-chrome_android"><span class="bc-head-txt-label bc-head-icon-chrome_android">Chrome for Android</span></th><th class="bc-browser-edge_mobile"><span class="bc-head-txt-label bc-head-icon-edge_mobile">Edge Mobile</span></th><th class="bc-browser-firefox_android"><span class="bc-head-txt-label bc-head-icon-firefox_android">Firefox for Android</span></th><th class="bc-browser-opera_android"><span class="bc-head-txt-label bc-head-icon-opera_android">Opera for Android</span></th><th class="bc-browser-safari_ios"><span class="bc-head-txt-label bc-head-icon-safari_ios">Safari on iOS</span></th><th class="bc-browser-samsunginternet_android"><span class="bc-head-txt-label bc-head-icon-samsunginternet_android">Samsung Internet</span></th><th class="bc-browser-nodejs"><span class="bc-head-txt-label bc-head-icon-nodejs">Node.js</span></th></tr></thead><tbody><tr><th scope="row"><code>set</code></th><td class="bc-supports-yes bc-browser-chrome"><span class="bc-browser-name">Chrome</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
38</td><td class="bc-supports-yes bc-browser-edge"><span class="bc-browser-name">Edge</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
12</td><td class="bc-supports-yes bc-browser-firefox"><span class="bc-browser-name">Firefox</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
13</td><td class="bc-supports-partial bc-browser-ie bc-has-history"><span class="bc-browser-name">IE</span><abbr class="bc-level-partial only-icon" title="Partial support">
<span>Partial support</span>
</abbr>11<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div><section class="bc-history" id="sect2"><dl><dt class="bc-supports-partial bc-supports"><abbr class="bc-level-partial only-icon" title="Partial support">
<span>Partial support</span>
</abbr>11<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div></dt><dd><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> Returns 'undefined' instead of the 'Map' object.</dd></dl></section></td><td class="bc-supports-yes bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
25</td><td class="bc-supports-yes bc-browser-safari"><span class="bc-browser-name">Safari</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
8</td><td class="bc-supports-yes bc-browser-webview_android"><span class="bc-browser-name">WebView Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
38</td><td class="bc-supports-yes bc-browser-chrome_android"><span class="bc-browser-name">Chrome Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
38</td><td class="bc-supports-yes bc-browser-edge_mobile"><span class="bc-browser-name">Edge Mobile</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
12</td><td class="bc-supports-yes bc-browser-firefox_android"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
14</td><td class="bc-supports-yes bc-browser-opera_android"><span class="bc-browser-name">Opera Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
25</td><td class="bc-supports-yes bc-browser-safari_ios"><span class="bc-browser-name">Safari iOS</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
8</td><td class="bc-supports-yes bc-browser-samsunginternet_android"><span class="bc-browser-name">Samsung Internet Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-nodejs"><span class="bc-browser-name">nodejs</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td></tr></tbody></table><section class="bc-legend" id="sect3"><h3 class="offscreen" id="Legend">Legend</h3><dl><dt><span class="bc-supports-yes bc-supports">
<abbr class="bc-level bc-level-yes only-icon" title="Full support">
<span>Full support</span>
 
</abbr></span></dt><dd>Full support</dd><dt><span class="bc-supports-partial bc-supports">
<abbr class="bc-level bc-level-partial only-icon" title="Partial support">
<span>Partial support</span>
 
</abbr></span></dt><dd>Partial support</dd><dt><abbr class="only-icon" title="See implementation notes."><span>See implementation notes.</span><i class="ic-footnote"></i></abbr></dt><dd>See implementation notes.</dd></dl></section></div><p></p>
<h2 id="参见">参见</h2>
<ul>
<li><a href="Reference/Map" title="此页面仍未被本地化, 期待您的翻译!"><code>Map</code></a></li>
<li><a href="Reference/Global_Objects/Map/get" title="get() 方法返回某个 Map 对象中的一个指定元素。"><code>Map.prototype.get()</code></a></li>
<li><a href="Reference/Global_Objects/Map/has" title="方法has() 返回一个bool值用来表明map 中是否存在指定元素."><code>Map.prototype.has()</code></a></li>
</ul>
</article>