空语句用来表明没有语句，尽管 JavaScript 语法希望有语句。

## 语法

    ;

## 描述

空语句是一个分号（;），表示不会执行任何语句，即使 JavaScript 语法需要一个语句。 相反，当你需要多行语句，但 JavaScript 只允许一个时，可以使用语句块；语句块可以将多条语句合并为一个。

## 示例

空语句有时与循环语句一起使用。以下示例使用空循环体：

    var arr = [1, 2, 3];

    // Assign all array values to 0
    for (let i = 0; i < arr.length; arr[i++] = 0) /* empty statement */ ;

    console.log(arr)
    // [0, 0, 0]

提示：在使用空语句的情况下专门写上注释是个不错的主意，因为不是很容易区分空语句和普通的分号。下面的示例可能不是故意加上分号的：

    if (condition);       // Caution, this "if" does nothing!
       killTheUniverse()  // So this gets always executed!!!

另一个例子：`if...else` 语句不带花括号（`{}`）。如果`three`为`true`, 不会发生任何事，`four`不会执行，同时`else`从句中的`launchRocket()`函数也不会执行。

    if (one)
      doOne();
    else if (two)
      doTwo();
    else if (three)
      ; // nothing here
    else if (four)
      doFour();
    else
      launchRocket();

## 规范

Specification | Status | Comment
--- | --- | ---
ECMAScript Latest Draft (ECMA-262) Empty statement | Draft |
ECMAScript 2015 (6th Edition, ECMA-262) Empty statement | Standard |
ECMAScript 5.1 (ECMA-262) Empty statement | Standard |
ECMAScript 3rd Edition (ECMA-262) Empty statement | Standard |
ECMAScript 1st Edition (ECMA-262) Empty statement | Standard | Initial definition.

## 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
Empty statement (`;`) | Chrome Full support Yes | Edge Full support Yes | 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

- `块语句`