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---
title: RegExp.lastParen ($+)
slug: Web/JavaScript/Reference/Global_Objects/RegExp/lastParen
translation_of: Web/JavaScript/Reference/Global_Objects/RegExp/lastParen
---
<div>{{JSRef}} {{non-standard_header}}</div>
<p><strong>lastParen </strong>非标准属性是正则表达式的静态和只读属性,包含匹配到的最后一个子串(如果存在)。<code>RegExp.$+</code>是这一属性的别名。</p>
<h2 id="语法">语法</h2>
<pre class="syntaxbox"><var>RegExp</var>.lastParen
RegExp['$+']
</pre>
<h2 id="描述">描述</h2>
<p><code>lastParen</code> 属性是静态的,不是正则表达式独立对象的属性。反之,你应始终将其使用为 <code>RegExp.lastParen</code> 或者 <code>RegExp['$+']</code>。</p>
<p><code>lastParen</code> 属性的值是只读的,并且会在匹配成功时修改。</p>
<p>你不能使用属性访问器(<code>RegExp.$+</code>)来使用简写的别名,因为解析器在这里会将 "+" 看做表达式,并抛出 {{jsxref("SyntaxError")}} 。使用 <a href="/en-US/docs/Web/JavaScript/Reference/Operators/Property_Accessors">方括号符号</a>来访问属性。</p>
<h2 id="示例">示例</h2>
<h3 id="使用_lastParen_和">使用 <code>lastParen</code> 和 <code>$+</code></h3>
<pre class="brush: js">var re = /(hi)/g;
re.test('hi there!');
RegExp.lastParen; // "hi"
RegExp['$+']; // "hi"
</pre>
<h2 id="规范">规范</h2>
<p>非标准。并不是任何现行规范的一部分。</p>
<h2 id="浏览器兼容性">浏览器兼容性</h2>
<div>{{CompatibilityTable}}</div>
<div id="compat-desktop">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Chrome</th>
<th>Firefox (Gecko)</th>
<th>Internet Explorer</th>
<th>Opera</th>
<th>Safari</th>
</tr>
<tr>
<td>Basic support</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
</tr>
</tbody>
</table>
</div>
<div id="compat-mobile">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Android</th>
<th>Chrome for Android</th>
<th>Firefox Mobile (Gecko)</th>
<th>IE Mobile</th>
<th>Opera Mobile</th>
<th>Safari Mobile</th>
</tr>
<tr>
<td>Basic support</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
</tr>
</tbody>
</table>
</div>
<h2 id="另见">另见</h2>
<ul>
<li>{{non-standard_inline}} {{jsxref("RegExp.input", "RegExp.input ($_)")}}</li>
<li>{{non-standard_inline}} {{jsxref("RegExp.lastMatch", "RegExp.lastMatch ($&)")}}</li>
<li>{{non-standard_inline}} {{jsxref("RegExp.leftContext", "RegExp.leftContext ($`)")}}</li>
<li>{{non-standard_inline}} {{jsxref("RegExp.rightContext", "RegExp.rightContext ($')")}}</li>
<li>{{non-standard_inline}} {{jsxref("RegExp.n", "RegExp.$1-$9")}}</li>
</ul>
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