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String.prototype.valueOf()

valueOf() 方法返回一个String对象的原始值(primitive value)。

语法

str.valueOf()

描述

String 对象的 valueOf 方法返回一个String对象的原始值。该值等同于String.prototype.toString()

该方法通常在 JavaScript 内部被调用,而不是在代码里显示调用。

示例

例子:使用 valueOf

x = new String("Hello world");
alert(x.valueOf())          // Displays "Hello world"

规范

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

浏览器兼容性

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) (Yes) (Yes) (Yes) (Yes)
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

相关链接

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