## 概述

`toString()` 方法返回指定对象的字符串形式。

## 语法

    str.toString()

## 描述

`String` 对象覆盖了`Object` 对象的 `toString` 方法；并没有继承 `Object.toString()`。对于 `String` 对象，`toString` 方法返回该对象的字符串形式，和 `String.prototype.valueOf()` 方法返回值一样。

## 示例

### 例子：使用 `toString`

下例输出一个字符串对象（String object）的字符串值：

    var x = new String("Hello world");

    alert(x.toString())      // 输出 "Hello world"

## 规范

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

## 浏览器兼容性

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

- Desktop
- Mobile

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

- `Object.prototype.toSource()`
- `String.prototype.valueOf()`