`Intl.NumberFormat.prototype.format` 属性返回一个根据`NumberFormat`对象的语言环境和格式化选项，来格式化一个数字的getter函数。

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## 语法

    numberFormat.format(number)

### 参数

`number`
  要格式化的数值。

## 描述

该函数返回一个根据`NumberFormat`对象的语言环境和格式化选项，来`format` 一个数字的函数。

## 示例

### 使用 `format`

使用 `format` 格式化一个单一的货币值, 以俄罗斯为例:

    var options = { style: 'currency', currency: 'RUB' };
    var numberFormat = new Intl.NumberFormat('ru-RU', options);
    console.log(numberFormat.format(654321.987));
    // → "654 321,99 руб."

### 使用 `format` 和 `map`

使用 `format` 返回的函数来格式化数组中的所有数字。注意，该函数绑定到所获得的`NumberFormat`，因此它可以直接传递给`Array.prototype.map`。

    var a = [123456.789, 987654.321, 456789.123];
    var numberFormat = new Intl.NumberFormat('es-ES');
    var formatted = a.map(numberFormat.format);
    console.log(formatted.join('; '));
    // → "123.456,789; 987.654,321; 456.789,123"

## 规范

规范 | 状态 | 注解
--- | --- | ---
ECMAScript Internationalization API 1.0 (ECMA-402) Intl.NumberFormat.prototype.format | Standard | 初始定义
ECMAScript Internationalization API 2.0 (ECMA-402) Intl.NumberFormat.prototype.format | Standard |
ECMAScript Internationalization API 4.0 (ECMA-402) Intl.NumberFormat.prototype.format | Draft |

## 浏览器兼容性

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-dataand 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
`format` | Chrome Full support 24 | Edge Full support Yes | Firefox Full support 29 | IE Full support 11 | Opera Full support 15 | Safari Full support 10 | WebView Android Full support Yes | Chrome Android Full support 26 | Edge Mobile Full support Yes | Firefox Android Full support 56 | Opera Android ? | Safari iOS Full support 10 | Samsung Internet Android Full support Yes | nodejs ?

### Legend

Full support
  Full support
Compatibility unknown
  Compatibility unknown

## 相关链接

- `Intl.NumberFormat`
- `Number.prototype.toLocaleString()`