`clear()`方法会移除Map对象中的所有元素。

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

## 语法

    myMap.clear();

### 返回值

`undefined`.

## 示例

### 调用`clear`方法

    var myMap = new Map();
    myMap.set("bar", "baz");
    myMap.set(1, "foo");

    myMap.size;       // 2
    myMap.has("bar"); // true

    myMap.clear();

    myMap.size;       // 0
    myMap.has("bar")  // false

## 规范

Specification | Status | Comment
--- | --- | ---
ECMAScript 2015 (6th Edition, ECMA-262) Map.prototype.clear | Standard | Initial definition.
ECMAScript Latest Draft (ECMA-262) Map.prototype.clear | 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
`clear` | Chrome Full support 38 | Edge Full support 12 | Firefox Full support 19 | IE Full support 11 | Opera Full support 25 | Safari Full support 8 | WebView Android Full support 38 | Chrome Android Full support 38 | Edge Mobile Full support 12 | Firefox Android Full support 19 | Opera Android Full support 25 | Safari iOS Full support 8 | Samsung Internet Android Full support Yes | nodejs Full support 0.12

### Legend

Full support
  Full support

## 相关链接

- `Map`