---
title: RegExp.prototype.multiline
slug: Web/JavaScript/Reference/Global_Objects/RegExp/multiline
tags:
  - JavaScript
  - Property
  - Prototype
  - RegExp
  - Regular Expressions
translation_of: Web/JavaScript/Reference/Global_Objects/RegExp/multiline
---
<div>
 {{JSRef("Global_Objects", "RegExp")}}</div>
<h2 id="Summary" name="Summary">概述</h2>
<p><code><strong>multiline</strong></code> 属性表明正则表达式是否使用了 "<code>m</code>" 标志。<code>multiline</code> 是正则表达式实例的一个只读属性。</p>
<div>
 {{js_property_attributes(0,0,0)}}</div>
<h2 id="Description" name="Description">描述</h2>
<p><code>multiline</code> 是一个布尔对象，如果使用了 "<code>m</code>" 标志，则返回 <code>true</code>；否则，返回 <code>false</code>。"<code>m</code>" 标志意味着一个多行输入字符串被看作多行。例如，使用 "<code>m</code>"，"<code>^</code>" 和 "<code>$</code>" 将会从只匹配正则字符串的开头或结尾，变为匹配字符串中任一行的开头或结尾。</p>
<p>你无法直接更改此属性。</p>
<h2 id="Examples" name="Examples">示例</h2>
<h3 id="Example:_Using_MIN_VALUE" name="Example:_Using_MIN_VALUE">例子：使用 <code>multiline</code></h3>
<pre class="brush:js">var regex = new RegExp("foo", "m")

console.log(regex.multiline) // true
</pre>
<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>ECMAScript 3rd Edition. Implemented in JavaScript 1.2.</td>
   <td>Standard</td>
   <td>Initial definition.<br>
    JavaScript 1.5: <code>multiline</code> is a property of a <code>RegExp</code> instance, not the <code>RegExp</code> object.</td>
  </tr>
  <tr>
   <td>{{SpecName('ES5.1', '#sec-15.10.7.4', 'RegExp.prototype.multiline')}}</td>
   <td>{{Spec2('ES5.1')}}</td>
   <td> </td>
  </tr>
  <tr>
   <td>{{SpecName('ES6', '#sec-get-regexp.prototype.multiline', 'RegExp.prototype.multiline')}}</td>
   <td>{{Spec2('ES6')}}</td>
   <td><code>multiline</code> is now a prototype accessor property rather than an instance's own data property.</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</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="See_also" name="See_also">相关链接</h2>
<ul>
 <li>{{jsxref("RegExp.prototype.global")}}</li>
 <li>{{jsxref("RegExp.prototype.lastIndex")}}</li>
 <li>{{jsxref("RegExp.prototype.ignoreCase")}}</li>
 <li>{{jsxref("RegExp.prototype.source")}}</li>
 <li>{{jsxref("RegExp.prototype.sticky")}}</li>
</ul>