uTools-Manuals/docs/javascript/Reference/Global_Objects/String/concat.html

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<p><strong><code>concat()</code></strong> 方法将一个或多个字符串与原字符串连接合并，形成一个新的字符串并返回。</p>
<h2 id="Syntax" name="Syntax">语法</h2>
<pre><code><var>str</var>.concat(<var>string2</var>, <var>string3</var>[, ..., <var>stringN</var>])</code></code></pre>
<h3 id="Parameters" name="Parameters">参数</h3>
<dl>
<dt><code>string2...string<em>N</em></code></dt>
<dd>和原字符串连接的多个字符串</dd>
</dl>
<h2 id="Description" name="Description">描述</h2>
<p><code>concat</code> 方法将一个或多个字符串与原字符串连接合并，形成一个新的字符串并返回。 <code>concat</code> 方法并不影响原字符串。</p>
<h2 id="Examples" name="Examples">示例</h2>
<h3 id="Examples" name="Examples">例子：使用 <code>concat</code></h3>
<p>下面的例子演示如何将多个字符串与原字符串合并为一个新字符串</p>
<pre><code  class="language-javascript">var hello = "Hello, ";
console.log(hello.concat("Kevin", " have a nice day.")); /* Hello, Kevin have a nice day. */
</code></pre>
<h2 id="性能" style="margin-bottom: 20px; line-height: 30px;">性能</h2>
<p>强烈建议使用 <a href="https://developer.mozilla.orgReference/Operators/Assignment_Operators">赋值操作符</a>（+, +=）代替 <code>concat</code> 方法。参看 <a class="external" href="http://jsperf.com/concat-vs-plus-vs-join" rel="noopener">性能测试（perfomance test）</a>。</p>
<h2 id="规范">规范</h2>
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<th scope="col">Specification</th>
<th scope="col">Status</th>
<th scope="col">Comment</th>
</tr>
<tr>
<td><a class="external" href="https://www.ecma-international.org/publications/files/ECMA-ST-ARCH/ECMA-262,%203rd%20edition,%20December%201999.pdf" hreflang="en" lang="en" rel="noopener" title="ECMAScript 3rd Edition (ECMA-262)">ECMAScript 3rd Edition (ECMA-262)</a></td>
<td><span class="spec-Standard">Standard</span></td>
<td>Initial definition. Implemented in JavaScript 1.2.</td>
</tr>
<tr>
<td><a class="external" href="https://www.ecma-international.org/ecma-262/5.1/#sec-15.5.4.6" hreflang="en" lang="en" rel="noopener">ECMAScript 5.1 (ECMA-262)<br/><small lang="zh-CN">String.prototype.concat</small></a></td>
<td><span class="spec-Standard">Standard</span></td>
<td> </td>
</tr>
<tr>
<td><a class="external" href="https://www.ecma-international.org/ecma-262/6.0/#sec-string.prototype.concat" hreflang="en" lang="en" rel="noopener">ECMAScript 2015 (6th Edition, ECMA-262)<br/><small lang="zh-CN">String.prototype.concat</small></a></td>
<td><span class="spec-Standard">Standard</span></td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容性">浏览器兼容性</h2>
<div><div class="blockIndicator warning"><strong><a class="external" href="https://github.com/mdn/browser-compat-data" rel="noopener">We're converting our compatibility data into a machine-readable JSON format</a></strong>.
            This compatibility table still uses the old format,
            because we haven't yet converted the data it contains.
            <strong><a class="new" href="/zh-CN/docs/MDN/Contribute/Structures/Compatibility_tables" rel="nofollow">Find out how you can help!</a></strong></div>
<div class="htab">
<a id="AutoCompatibilityTable" name="AutoCompatibilityTable"></a>
<ul>
<li class="selected"><a>Desktop</a></li>
<li><a>Mobile</a></li>
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<div id="compat-desktop">
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<th>Feature</th>
<th>Chrome</th>
<th>Firefox (Gecko)</th>
<th>Internet Explorer</th>
<th>Opera</th>
<th>Safari</th>
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<td>Basic support</td>
<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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</tbody>
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</div>
<div id="compat-mobile">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Android</th>
<th>Chrome for Android</th>
<th>Firefox Mobile (Gecko)</th>
<th>IE Mobile</th>
<th>Opera Mobile</th>
<th>Safari Mobile</th>
</tr>
<tr>
<td>Basic support</td>
<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
</tr>
</tbody>
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<h2 id="相关链接">相关链接</h2>
<ul>
<li><a href="Reference/Global_Objects/Array/concat" title="concat() 方法用于合并两个或多个数组。此方法不会更改现有数组，而是返回一个新数组。"><code>Array.prototype.concat()</code></a></li>
<li><a href="Reference/Operators/Assignment_Operators" title="赋值运算符（assignment operator）基于右值（right operand）的值，给左值（left operand）赋值。">Assignment operators</a></li>
</ul>
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