Boolean.prototype.valueOf()

valueOf() 方法返回一个Boolean对象的原始值。

语法

bool.valueOf()

返回值

给定Boolean对象的原始值

描述

Boolean的 valueOf 方法返回一个Boolean对象或Boolean字面量的原始值作为布尔数据类型。

该方法通常在 JavaScript 内部调用，而不是在代码中显式调用。

示例

使用 valueOf

x = new Boolean();
myVar = x.valueOf()      // assigns false to myVar

规范

Specification Status Comment
ECMAScript 1st Edition (ECMA-262) Standard Initial definition. Implemented in JavaScript 1.1.
ECMAScript 5.1 (ECMA-262)
Boolean.prototype.valueOf		 Standard  
ECMAScript 2015 (6th Edition, ECMA-262)
Boolean.prototype.valueOf		 Standard  
ECMAScript Latest Draft (ECMA-262)
Boolean.prototype.valueOf		 Draft  

浏览器兼容

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
valueOfChrome Full support 1Edge Full support 12Firefox Full support 1IE Full support 4Opera Full support YesSafari Full support YesWebView Android Full support 1Chrome Android Full support 18Firefox Android Full support 4Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support 1.0nodejs Full support Yes

Legend

Full support  
Full support

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  1. JavaScript 标准库
  2. Boolean
  3. 属性
    1. Boolean.prototype
  4. 方法
    1. Boolean.prototype.toSource()
    2. Boolean.prototype.toString()
    3. Boolean.prototype.valueOf()
  5. 继承
  6. Function
  7. 属性
    1. Function.arguments
    2. Function.arity
    3. Function.caller
    4. Function.displayName
    5. Function.length
    6. Function.name
    7. Function.prototype
  8. 方法
    1. Function.prototype.apply()
    2. Function.prototype.bind()
    3. Function.prototype.call()
    4. Function.prototype.isGenerator()
    5. Function.prototype.toSource()
    6. Function.prototype.toString()
  9. Object
  10. 属性
    1. Object.prototype.__count__
    2. Object.prototype.__noSuchMethod__
    3. Object.prototype.__parent__
    4. Object.prototype.__proto__
    5. Object.prototype.constructor
  11. 方法
    1. Object.prototype.__defineGetter__()
    2. Object.prototype.__defineSetter__()
    3. Object.prototype.__lookupGetter__()
    4. Object.prototype.__lookupSetter__()
    5. Object.prototype.hasOwnProperty()
    6. Object.prototype.isPrototypeOf()
    7. Object.prototype.propertyIsEnumerable()
    8. Object.prototype.toLocaleString()
    9. Object.prototype.toSource()
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    12. Object.prototype.valueOf()
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    14. Object.setPrototypeOf()