---
title: Boolean.prototype.toString()
slug: Web/JavaScript/Reference/Global_Objects/Boolean/toString
tags:
  - Boolean
  - JavaScript
  - Method
  - Prototype
translation_of: Web/JavaScript/Reference/Global_Objects/Boolean/toString
---
<div>{{JSRef}}</div>

<p><code><strong>toString()</strong></code> 方法返回指定的布尔对象的字符串形式。</p>

<div>{{EmbedInteractiveExample("pages/js/boolean-tostring.html")}}</div>



<h2 id="Syntax">语法</h2>

<pre class="syntaxbox"><var>bool</var>.toString()</pre>

<h3 id="返回值">返回值</h3>

<p>表示特定{{jsxref("Boolean")}}对象的字符串。</p>

<h2 id="Description">描述</h2>

<p>{{jsxref("Boolean")}} 对象覆盖了 {{jsxref("Object")}} 对象的  <code>toString</code> 方法。并没有继承 {{jsxref("Object.prototype.toString()")}}。对于布尔对象，<code>toString</code> 方法返回该对象的字符串形式。</p>

<p>当一个{{jsxref("Boolean")}}对象作为文本值或进行字符串连接时，JavaScript 会自动调用其 <code>toString</code> 方法。</p>

<p>对于{{jsxref("Boolean")}}对象或值，内置的 <code>toString</code> 方法返回字符串 "<code>true</code>" 或 "<code>false</code>"，具体返回哪个取决于布尔对象的值。</p>

<h2 id="示例">示例</h2>

<h3 id="使用_toString">使用 <code>toString</code></h3>

<p>下面的代码，<code>flag.toString</code> 返回 "<code>true</code>"：</p>

<pre class="brush: js">var flag = new Boolean(true)
var myVar = flag.toString()
</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('ES1')}}</td>
   <td>{{Spec2('ES1')}}</td>
   <td>Initial definition.</td>
  </tr>
  <tr>
   <td>{{SpecName('ES5.1', '#sec-15.6.4.2', 'Boolean.prototype.toString')}}</td>
   <td>{{Spec2('ES5.1')}}</td>
   <td> </td>
  </tr>
  <tr>
   <td>{{SpecName('ES6', '#sec-boolean.prototype.tostring', 'Boolean.prototype.toString')}}</td>
   <td>{{Spec2('ES6')}}</td>
   <td> </td>
  </tr>
  <tr>
   <td>{{SpecName('ESDraft', '#sec-boolean.prototype.tostring', 'Boolean.prototype.toString')}}</td>
   <td>{{Spec2('ESDraft')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="浏览器兼容">浏览器兼容</h2>

<p>{{Compat("javascript.builtins.Boolean.toString")}}</p>

<h2 id="See_Also">相关链接</h2>

<ul>
 <li>{{jsxref("Object.prototype.toString()")}}</li>
</ul>