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<article id="wikiArticle">
<p></p><p></p>
<p><strong><code>Boolean</code></strong>对象是一个布尔值的对象包装器。</p>
<h2 id="Syntax" name="Syntax">语法</h2>
<pre><code class="language-javascript">new Boolean([<var>value</var>])</code></pre>
<h3 id="参数">参数</h3>
<dl>
<dt><code>value</code></dt>
<dd> 可选，用来初始化 <code>Boolean</code> 对象的值。</dd>
</dl>
<h2 id="Description" name="Description">描述</h2>
<p>如果第一个参数不是布尔值，则会将其转换为布尔值。如果省略该参数，或者其值为 <code>0</code>、<code>-0</code>、<a href="Reference/Global_Objects/null" title="值 null 特指对象的值未设置。它是 JavaScript 基本类型 之一。"><code>null</code></a>、<code>false</code>、<a href="Reference/Global_Objects/NaN" title="全局属性 NaN 的值表示不是一个数字（Not-A-Number）。"><code>NaN</code></a>、<a href="Reference/Global_Objects/undefined" title="undefined是全局对象的一个属性。也就是说，它是全局作用域的一个变量。undefined的最初值就是原始数据类型undefined。"><code>undefined</code></a>、或者空字符串（<code>""</code>），则生成的 <code>Boolean</code> 对象的值为 <code>false</code>。如果传入的参数是 DOM 对象  <a href="/zh-CN/docs/Web/API/Document/all" title="The Document interface's read-only all property returns an HTMLAllCollection rooted at the document node. In other words, it returns the entire contents of the page."><code>document.all</code></a>，也会生成值为 <code>false</code> 的 <code>Boolean</code> 对象。任何其他的值，包括值为 <code>"false"</code> 的字符串和任何对象，都会创建一个值为 <code>true</code> 的 <code>Boolean</code> 对象。</p>
<p>注意不要将基本类型中的布尔值 <code>true</code> 和 <code>false</code> 与值为 <code>true</code> 和 <code>false</code> 的 <code>Boolean</code> 对象弄混了。</p>
<p>当 <code>Boolean</code> 对象用于条件语句的时候（译注：意为直接应用于条件语句），任何不是 <a href="Reference/Global_Objects/undefined" title="undefined是全局对象的一个属性。也就是说，它是全局作用域的一个变量。undefined的最初值就是原始数据类型undefined。"><code>undefined</code></a> 和 <a href="Reference/Global_Objects/null" title="值 null 特指对象的值未设置。它是 JavaScript 基本类型 之一。"><code>null</code></a> 的对象，包括值为 <code>false</code> 的 <code>Boolean</code> 对象，都会被当做 <code>true</code> 来对待。例如，下面 <a href="Reference/Statements/if...else" title="当指定条件为真，if 语句会执行一段语句。如果条件为假，则执行另一段语句。"><code>if</code></a> 语句中的条件为真:</p>
<pre><code class="language-javascript">var x = new Boolean(false);
if (x) {
// 这里的代码会被执行
}
</code></pre>
<p>基本类型的布尔值不受此规则影响。例如下面的 <a href="Reference/Statements/if...else" title="当指定条件为真，if 语句会执行一段语句。如果条件为假，则执行另一段语句。"><code>if</code></a> 语句的条件为假：</p>
<pre><code class="language-javascript">var x = false;
if (x) {
// 这里的代码不会执行
}
</code></pre>
<p>不要用创建 <code>Boolean</code> 对象的方式将一个非布尔值转化成布尔值，直接将 <code>Boolean</code> 当做转换函数来使用即可：</p>
<pre><code class="language-javascript">var x = Boolean(expression); // 推荐
var x = new Boolean(expression); // 不太好
</code></pre>
<p>对于任何对象，即使是值为 <code>false</code> 的 <code>Boolean</code> 对象，当将其传给 <code>Boolean</code> 函数时，生成的 <code>Boolean</code> 对象的值都是 <code>true</code>。</p>
<pre><code class="language-javascript">var myFalse = new Boolean(false); // false
var g = new Boolean(myFalse); // true
var myString = new String("Hello");
var s = new Boolean(myString); // true
</code></pre>
<p>最后，不要在应该使用基本类型布尔值的地方使用 <code>Boolean</code> 对象。</p>
<h2 id="Properties" name="Properties">属性</h2>
<dl>
<dt><code>Boolean.length</code></dt>
<dd><code>length</code> 属性，值为 1。</dd>
<dt><a href="Reference/Global_Objects/Boolean/prototype" title="Boolean.prototype 属性表示Boolean 构造函数的原型。"><code>Boolean.prototype</code></a></dt>
<dd><code>Boolean</code> 构造函数的原型对象。</dd>
</dl>
<h2 id="Methods" name="Methods">方法</h2>
<p><code>Boolean</code> 对象自身没有任何方法，不过它从自己的原型链上继承了一些方法，见下面的“<code>Boolean</code> 实例”小节。</p>
<h2 id="Boolean_instances" name="Boolean_instances"><code>Boolean</code> 实例</h2>
<p>所有 <code>Boolean</code> 实例都继承于 <a href="Reference/Global_Objects/Boolean/prototype" title="Boolean.prototype 属性表示Boolean 构造函数的原型。"><code>Boolean.prototype</code></a>。与所有的构造函数一样，<code>Boolean</code> 的原型对象为其实例提供继承属性和方法。</p>
<h3 id="属性">属性</h3>
<div><dl>
<dt><code>Boolean.prototype.constructor</code></dt>
<dd>返回创建了实例原型的函数。默认为<a href="Reference/Boolean" title="此页面仍未被本地化, 期待您的翻译!"><code>Boolean</code></a>函数。</dd>
</dl></div>
<h3 id="方法">方法</h3>
<div><dl>
<dt><a href="Reference/Global_Objects/Boolean/toSource" title="toSource（）方法返回一个表示对象的源码的字符串。"><code>Boolean.prototype.toSource()</code></a> <span class="icon-only-inline" title="This API has not been standardized."><i class="icon-warning-sign"> </i></span></dt>
<dd>返回包含<a href="Reference/Boolean" title="此页面仍未被本地化, 期待您的翻译!"><code>Boolean</code></a>对象源码的字符串；你可以使用这个字符串来创建一个等价的对象。覆盖了<a href="Reference/Global_Objects/Object/toSource" title="toSource()方法返回一个表示对象源代码的字符串。"><code>Object.prototype.toSource()</code></a> 方法。</dd>
<dt><a href="Reference/Global_Objects/Boolean/toString" title="toString() 方法返回指定的布尔对象的字符串形式。"><code>Boolean.prototype.toString()</code></a></dt>
<dd>根据对象的值来返回一个字符串：<code>"true"</code> 或 <code>"false"</code>。覆盖了 <a href="Reference/Global_Objects/Object/toString" title="toString() 方法返回一个表示该对象的字符串。"><code>Object.prototype.toString()</code></a> 方法。</dd>
<dt><a href="Reference/Global_Objects/Boolean/valueOf" title="valueOf() 方法返回一个Boolean对象的原始值。"><code>Boolean.prototype.valueOf()</code></a></dt>
<dd>返回<a href="Reference/Boolean" title="此页面仍未被本地化, 期待您的翻译!"><code>Boolean</code></a>对象的原始值。覆盖了 <a href="Reference/Global_Objects/Object/valueOf" title="valueOf() 方法返回指定对象的原始值。"><code>Object.prototype.valueOf()</code></a> 方法。</dd>
</dl></div>
<h2 id="Examples" name="Examples">示例</h2>
<h3 id="Creating_Boolean_objects_with_an_initial_value_of_false" name="Creating_Boolean_objects_with_an_initial_value_of_false">创建值为 <code>false</code> 的 <code>Boolean</code> 对象</h3>
<pre><code class="language-javascript">var bNoParam = new Boolean();
var bZero = new Boolean(0);
var bNull = new Boolean(null);
var bEmptyString = new Boolean('');
var bfalse = new Boolean(false);
</code></pre>
<h3 id="Creating_Boolean_objects_with_an_initial_value_of_false" name="Creating_Boolean_objects_with_an_initial_value_of_false">创建值为 <code>true</code> 的  <code>Boolean</code> 对象</h3>
<pre><code class="language-javascript">var btrue = new Boolean(true);
var btrueString = new Boolean('true');
var bfalseString = new Boolean('false');
var bSuLin = new Boolean('Su Lin');
var bArrayProto = new Boolean([]);
var bObjProto = new Boolean({});
</code></pre>
<h2 id="规范">规范</h2>
<table class="standard-table">
<tbody>
<tr>
<th scope="col">规范</th>
<th scope="col">状态</th>
<th scope="col">说明</th>
</tr>
<tr>
<td><a class="external" href="https://www.ecma-international.org/publications/files/ECMA-ST-ARCH/ECMA-262,%201st%20edition,%20June%201997.pdf" hreflang="en" lang="en" rel="noopener" title="ECMAScript 1st Edition (ECMA-262)">ECMAScript 1st Edition (ECMA-262)</a></td>
<td><span class="spec-Standard">Standard</span></td>
<td>初始定义，在 JavaScript 1.0 中实现</td>
</tr>
<tr>
<td><a class="external" href="https://www.ecma-international.org/ecma-262/5.1/#sec-15.6" hreflang="en" lang="en" rel="noopener">ECMAScript 5.1 (ECMA-262)<br/><small lang="zh-CN">Boolean</small></a></td>
<td><span class="spec-Standard">Standard</span></td>
<td> </td>
</tr>
<tr>
<td><a class="external" href="https://www.ecma-international.org/ecma-262/6.0/#sec-boolean-objects" hreflang="en" lang="en" rel="noopener">ECMAScript 2015 (6th Edition, ECMA-262)<br/><small lang="zh-CN">Boolean</small></a></td>
<td><span class="spec-Standard">Standard</span></td>
<td> </td>
</tr>
<tr>
<td><a class="external" href="https://tc39.github.io/ecma262/#sec-boolean-objects" hreflang="en" lang="en" rel="noopener">ECMAScript Latest Draft (ECMA-262)<br/><small lang="zh-CN">Boolean</small></a></td>
<td><span class="spec-Draft">Draft</span></td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容性">浏览器兼容性</h2>
<div class="hidden">The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out <a class="external" href="https://github.com/mdn/browser-compat-data" rel="noopener">https://github.com/mdn/browser-compat-data</a> and send us a pull request.</div>
<p></p><div class="bc-data"><a class="bc-github-link external" href="https://github.com/mdn/browser-compat-data" rel="noopener">Update compatibility data on GitHub</a><table class="bc-table bc-table-js"><thead><tr class="bc-platforms"><td></td><th class="bc-platform-desktop" colspan="6"><span>Desktop</span></th><th class="bc-platform-mobile" colspan="7"><span>Mobile</span></th><th class="bc-platform-server" colspan="1"><span>Server</span></th></tr><tr class="bc-browsers"><td></td><th class="bc-browser-chrome"><span class="bc-head-txt-label bc-head-icon-chrome">Chrome</span></th><th class="bc-browser-edge"><span class="bc-head-txt-label bc-head-icon-edge">Edge</span></th><th class="bc-browser-firefox"><span class="bc-head-txt-label bc-head-icon-firefox">Firefox</span></th><th class="bc-browser-ie"><span class="bc-head-txt-label bc-head-icon-ie">Internet Explorer</span></th><th class="bc-browser-opera"><span class="bc-head-txt-label bc-head-icon-opera">Opera</span></th><th class="bc-browser-safari"><span class="bc-head-txt-label bc-head-icon-safari">Safari</span></th><th class="bc-browser-webview_android"><span class="bc-head-txt-label bc-head-icon-webview_android">Android webview</span></th><th class="bc-browser-chrome_android"><span class="bc-head-txt-label bc-head-icon-chrome_android">Chrome for Android</span></th><th class="bc-browser-edge_mobile"><span class="bc-head-txt-label bc-head-icon-edge_mobile">Edge Mobile</span></th><th class="bc-browser-firefox_android"><span class="bc-head-txt-label bc-head-icon-firefox_android">Firefox for Android</span></th><th class="bc-browser-opera_android"><span class="bc-head-txt-label bc-head-icon-opera_android">Opera for Android</span></th><th class="bc-browser-safari_ios"><span class="bc-head-txt-label bc-head-icon-safari_ios">Safari on iOS</span></th><th class="bc-browser-samsunginternet_android"><span class="bc-head-txt-label bc-head-icon-samsunginternet_android">Samsung Internet</span></th><th class="bc-browser-nodejs"><span class="bc-head-txt-label bc-head-icon-nodejs">Node.js</span></th></tr></thead><tbody><tr><th scope="row"><code>Boolean</code></th><td class="bc-supports-yes bc-browser-chrome"><span class="bc-browser-name">Chrome</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
1</td><td class="bc-supports-yes bc-browser-edge"><span class="bc-browser-name">Edge</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
12</td><td class="bc-supports-yes bc-browser-firefox"><span class="bc-browser-name">Firefox</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
1</td><td class="bc-supports-yes bc-browser-ie"><span class="bc-browser-name">IE</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-safari"><span class="bc-browser-name">Safari</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-webview_android"><span class="bc-browser-name">WebView Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-chrome_android"><span class="bc-browser-name">Chrome Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
18</td><td class="bc-supports-yes bc-browser-edge_mobile"><span class="bc-browser-name">Edge Mobile</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-firefox_android"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
4</td><td class="bc-supports-yes bc-browser-opera_android"><span class="bc-browser-name">Opera Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-safari_ios"><span class="bc-browser-name">Safari iOS</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-samsunginternet_android"><span class="bc-browser-name">Samsung Internet Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-nodejs"><span class="bc-browser-name">nodejs</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td></tr><tr><th scope="row"><a href="Reference/Global_Objects/Boolean/prototype"><code>prototype</code></a></th><td class="bc-supports-yes bc-browser-chrome"><span class="bc-browser-name">Chrome</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-edge"><span class="bc-browser-name">Edge</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
12</td><td class="bc-supports-yes bc-browser-firefox"><span class="bc-browser-name">Firefox</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
1</td><td class="bc-supports-yes bc-browser-ie"><span class="bc-browser-name">IE</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-safari"><span class="bc-browser-name">Safari</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-webview_android"><span class="bc-browser-name">WebView Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-chrome_android"><span class="bc-browser-name">Chrome Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-edge_mobile"><span class="bc-browser-name">Edge Mobile</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-firefox_android"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
4</td><td class="bc-supports-yes bc-browser-opera_android"><span class="bc-browser-name">Opera Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-safari_ios"><span class="bc-browser-name">Safari iOS</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-samsunginternet_android"><span class="bc-browser-name">Samsung Internet Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-nodejs"><span class="bc-browser-name">nodejs</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td></tr><tr><th scope="row"><a href="Reference/Global_Objects/Boolean/toSource"><code>toSource</code></a> <div class="bc-icons"><abbr class="only-icon" title="Non-standard. Expect poor cross-browser support."><span>Non-standard</span><i class="ic-non-standard"></i></abbr></div></th><td class="bc-supports-no bc-browser-chrome"><span class="bc-browser-name">Chrome</span><abbr class="bc-level-no only-icon" title="No support">
<span>No support</span>
</abbr>
No</td><td class="bc-supports-no bc-browser-edge"><span class="bc-browser-name">Edge</span><abbr class="bc-level-no only-icon" title="No support">
<span>No support</span>
</abbr>
No</td><td class="bc-supports-yes bc-browser-firefox"><span class="bc-browser-name">Firefox</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
1</td><td class="bc-supports-no bc-browser-ie"><span class="bc-browser-name">IE</span><abbr class="bc-level-no only-icon" title="No support">
<span>No support</span>
</abbr>
No</td><td class="bc-supports-no bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr class="bc-level-no only-icon" title="No support">
<span>No support</span>
</abbr>
No</td><td class="bc-supports-no bc-browser-safari"><span class="bc-browser-name">Safari</span><abbr class="bc-level-no only-icon" title="No support">
<span>No support</span>
</abbr>
No</td><td class="bc-supports-no bc-browser-webview_android"><span class="bc-browser-name">WebView Android</span><abbr class="bc-level-no only-icon" title="No support">
<span>No support</span>
</abbr>
No</td><td class="bc-supports-no bc-browser-chrome_android"><span class="bc-browser-name">Chrome Android</span><abbr class="bc-level-no only-icon" title="No support">
<span>No support</span>
</abbr>
No</td><td class="bc-supports-no bc-browser-edge_mobile"><span class="bc-browser-name">Edge Mobile</span><abbr class="bc-level-no only-icon" title="No support">
<span>No support</span>
</abbr>
No</td><td class="bc-supports-yes bc-browser-firefox_android"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
4</td><td class="bc-supports-no bc-browser-opera_android"><span class="bc-browser-name">Opera Android</span><abbr class="bc-level-no only-icon" title="No support">
<span>No support</span>
</abbr>
No</td><td class="bc-supports-no bc-browser-safari_ios"><span class="bc-browser-name">Safari iOS</span><abbr class="bc-level-no only-icon" title="No support">
<span>No support</span>
</abbr>
No</td><td class="bc-supports-no bc-browser-samsunginternet_android"><span class="bc-browser-name">Samsung Internet Android</span><abbr class="bc-level-no only-icon" title="No support">
<span>No support</span>
</abbr>
No</td><td class="bc-supports-no bc-browser-nodejs"><span class="bc-browser-name">nodejs</span><abbr class="bc-level-no only-icon" title="No support">
<span>No support</span>
</abbr>
No</td></tr><tr><th scope="row"><a href="Reference/Global_Objects/Boolean/toString"><code>toString</code></a></th><td class="bc-supports-yes bc-browser-chrome"><span class="bc-browser-name">Chrome</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-edge"><span class="bc-browser-name">Edge</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
12</td><td class="bc-supports-yes bc-browser-firefox"><span class="bc-browser-name">Firefox</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
1</td><td class="bc-supports-yes bc-browser-ie"><span class="bc-browser-name">IE</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-safari"><span class="bc-browser-name">Safari</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-webview_android"><span class="bc-browser-name">WebView Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-chrome_android"><span class="bc-browser-name">Chrome Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-edge_mobile"><span class="bc-browser-name">Edge Mobile</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-firefox_android"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
4</td><td class="bc-supports-yes bc-browser-opera_android"><span class="bc-browser-name">Opera Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-safari_ios"><span class="bc-browser-name">Safari iOS</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-samsunginternet_android"><span class="bc-browser-name">Samsung Internet Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-nodejs"><span class="bc-browser-name">nodejs</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td></tr><tr><th scope="row"><a href="Reference/Global_Objects/Boolean/valueOf"><code>valueOf</code></a></th><td class="bc-supports-yes bc-browser-chrome"><span class="bc-browser-name">Chrome</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-edge"><span class="bc-browser-name">Edge</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
12</td><td class="bc-supports-yes bc-browser-firefox"><span class="bc-browser-name">Firefox</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
1</td><td class="bc-supports-yes bc-browser-ie"><span class="bc-browser-name">IE</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-safari"><span class="bc-browser-name">Safari</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-webview_android"><span class="bc-browser-name">WebView Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-chrome_android"><span class="bc-browser-name">Chrome Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-edge_mobile"><span class="bc-browser-name">Edge Mobile</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-firefox_android"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
4</td><td class="bc-supports-yes bc-browser-opera_android"><span class="bc-browser-name">Opera Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-safari_ios"><span class="bc-browser-name">Safari iOS</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-samsunginternet_android"><span class="bc-browser-name">Samsung Internet Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td><td class="bc-supports-yes bc-browser-nodejs"><span class="bc-browser-name">nodejs</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td></tr></tbody></table><section class="bc-legend" id="sect1"><h3 class="offscreen" id="Legend">Legend</h3><dl><dt><span class="bc-supports-yes bc-supports">
<abbr class="bc-level bc-level-yes only-icon" title="Full support">
<span>Full support</span>
 
</abbr></span></dt><dd>Full support</dd><dt><span class="bc-supports-no bc-supports">
<abbr class="bc-level bc-level-no only-icon" title="No support">
<span>No support</span>
 
</abbr></span></dt><dd>No support</dd><dt><abbr class="only-icon" title="Non-standard. Expect poor cross-browser support."><span>Non-standard. Expect poor cross-browser support.</span><i class="ic-non-standard"></i></abbr></dt><dd>Non-standard. Expect poor cross-browser support.</dd></dl></section></div><p></p>
<h2 id="See_also" name="See_also">相关链接</h2>
<ul>
<li><a href="Reference/Global_Objects/Boolean/prototype" title="Boolean.prototype 属性表示Boolean 构造函数的原型。"><code>Boolean.prototype</code></a></li>
<li><a class="glossaryLink" href="/en-US/docs/Glossary/Boolean" title="Boolean: In computer science, a Boolean is a logical data type that can have only the values true or false.">Boolean</a></li>
<li><a class="external" href="http://en.wikipedia.org/wiki/Boolean_data_type" rel="noopener">Boolean data type (Wikipedia)</a></li>
</ul>
</article>
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