`toString()` 方法返回指定的布尔对象的字符串形式。

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## 语法

    bool.toString()

### 返回值

表示特定`Boolean`对象的字符串。

## 描述

`Boolean` 对象覆盖了 `Object` 对象的 `toString` 方法。并没有继承 `Object.prototype.toString()`。对于布尔对象，`toString` 方法返回该对象的字符串形式。

当一个`Boolean`对象作为文本值或进行字符串连接时，JavaScript 会自动调用其 `toString` 方法。

对于`Boolean`对象或值，内置的 `toString` 方法返回字符串 "`true`" 或 "`false`"，具体返回哪个取决于布尔对象的值。

## 示例

### 使用 `toString`

下面的代码，`flag.toString` 返回 "`true`"：

    var flag = new Boolean(true)
    var myVar = flag.toString()

## 规范

Specification | Status | Comment
--- | --- | ---
ECMAScript 1st Edition (ECMA-262) | Standard | Initial definition.
ECMAScript 5.1 (ECMA-262) Boolean.prototype.toString | Standard |
ECMAScript 2015 (6th Edition, ECMA-262) Boolean.prototype.toString | Standard |
ECMAScript Latest Draft (ECMA-262) Boolean.prototype.toString | Draft |

## 浏览器兼容

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

| Desktop | Mobile | Server
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | Android webview | Chrome for Android | Edge Mobile | Firefox for Android | Opera for Android | Safari on iOS | Samsung Internet | Node.js
`toString` | 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

### Legend

Full support
  Full support

## 相关链接

- `Object.prototype.toString()`