aboutsummaryrefslogtreecommitdiff
path: root/files/zh-cn/web/javascript/reference/global_objects/regexp/lastparen/index.html
blob: 0424c58ab3ff5451e529e249649aa6f7570ebaab (plain)
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
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
---
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><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 ($_)")}}</li>
 <li>{{non-standard_inline}} {{jsxref("RegExp.lastMatch", "RegExp.lastMatch ($&amp;)")}}</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>