---
title: RegExp.prototype.flags
slug: Web/JavaScript/Reference/Global_Objects/RegExp/flags
translation_of: Web/JavaScript/Reference/Global_Objects/RegExp/flags
---
<div>{{JSRef}}</div>

<p><strong><code>flags</code></strong>属性返回一个字符串，由当前正则表达式对象的标志组成。</p>

<div>{{js_property_attributes(0, 0, 1)}}</div>

<h2 id="描述">描述</h2>

<p><code>flags</code>属性中的标志以字典序排序（从左到右，即<code>"gimuy"</code>）。</p>

<h2 id="示例">示例</h2>

<h3 id="使用flags">使用<code>flags</code></h3>

<pre class="brush: js">/foo/ig.flags;   // "gi"
/bar/myu.flags;  // "muy"
</pre>

<h2 id="Polyfill">Polyfill</h2>

<pre class="brush: js">if (RegExp.prototype.flags === undefined) {
  Object.defineProperty(RegExp.prototype, 'flags', {
    configurable: true,
    get: function() {
      return this.toString().match(/[gimuy]*$/)[0];
    }
  });
}
</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>{{SpecName('ES2015', '#sec-get-regexp.prototype.flags', 'RegExp.prototype.flags')}}</td>
   <td>{{Spec2('ES2015')}}</td>
   <td>初始定义。</td>
  </tr>
  <tr>
   <td>{{SpecName('ESDraft', '#sec-get-regexp.prototype.flags', 'RegExp.prototype.flags')}}</td>
   <td>{{Spec2('ESDraft')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<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>{{CompatGeckoDesktop("37")}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatNo}}</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>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatGeckoMobile("37")}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="另见">另见</h2>

<ul>
 <li>{{jsxref("RegExp.prototype.source")}}</li>
</ul>