valueOf()
方法返回一个Boolean
对象的原始值。
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bool.valueOf()
给定Boolean
对象的原始值
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。
valueOf
x = new Boolean();
myVar = x.valueOf() // assigns false to myVar
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 |
Desktop | Mobile | Server | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
valueOf | Chrome Full support Yes | Edge Full support 12 | Firefox Full support 1 | IE Full support Yes | Opera Full support Yes | Safari Full support Yes | WebView Android Full support Yes | Chrome Android Full support Yes | Edge Mobile Full support Yes | Firefox Android Full support 4 | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes | nodejs Full support Yes |