---
title: RegExp.prototype.ignoreCase
slug: Web/JavaScript/Reference/Global_Objects/RegExp/ignoreCase
tags:
  - JavaScript
  - Property
  - Prototype
  - RegExp
translation_of: Web/JavaScript/Reference/Global_Objects/RegExp/ignoreCase
---
<div>
 {{JSRef("Global_Objects", "RegExp")}}</div>
<h2 id="Summary">概述</h2>
<p><code><strong>ignoreCase</strong></code> 属性表明正则表达式是否使用了 "<code>i</code>" 标志。<code>ignoreCase</code> 是正则表达式实例的只读属性。</p>
<div>
 {{js_property_attributes(0,0,0)}}</div>
<h2 id="Description">描述</h2>
<p><code>ignoreCase</code> 的值是布尔对象，如果使用了"<code>i</code>" 标志，则返回 <code>true</code>；否则，返回 <code>false</code>。"<code>i</code>" 标志意味着在字符串进行匹配时，应该忽略大小写。</p>
<p>你无法直接更改此属性。</p>
<h2 id="Examples">示例</h2>
<h3 id="Example:_Using_MIN_VALUE">例子：使用 <code>ignoreCase</code></h3>
<pre class="brush:js">var regex = new RegExp("foo", "i")

console.log(regex.ignoreCase) // 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>ignoreCase</code> is a property of a <code>RegExp</code> instance, not the <code>RegExp</code> object.</td>
  </tr>
  <tr>
   <td>{{SpecName('ES5.1', '#sec-15.10.7.3', 'RegExp.prototype.ignoreCase')}}</td>
   <td>{{Spec2('ES5.1')}}</td>
   <td> </td>
  </tr>
  <tr>
   <td>{{SpecName('ES6', '#sec-get-regexp.prototype.ignorecase', 'RegExp.prototype.ignoreCase')}}</td>
   <td>{{Spec2('ES6')}}</td>
   <td><code>ignoreCase</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>

{{Compat}}

<h2 id="See_also">相关链接</h2>
<ul>
 <li>{{jsxref("RegExp.prototype.global")}}</li>
 <li>{{jsxref("RegExp.prototype.lastIndex")}}</li>
 <li>{{jsxref("RegExp.prototype.multiline")}}</li>
 <li>{{jsxref("RegExp.prototype.source")}}</li>
 <li>{{jsxref("RegExp.prototype.sticky")}}</li>
</ul>