圆括号运算符`( )` 用来控制表达式中的运算优先级。

这些交互的事例资源都是基于Github的仓库.如果你想提交更多的交互事例,请克隆这个urlhttps://github.com/mdn/interactive-examples 并且向我们发送合并请求

## 语法

     ( )

## 说明

圆括号运算符由一对圆括号组成,包裹表达式和子表达式用来覆盖常规的 运算符优先级 ,达到低优先级的表达式比高优先级的表达式更早运算.

## 示例

下面的代码展示了加法运算先于乘法运算的情况.

    var a = 1;
    var b = 2;
    var c = 3;

    // default precedence
    a + b * c     // 7
    // evaluated by default like this
    a + (b * c)   // 7

    // now overriding precedence
    // addition before multiplication
    (a + b) * c   // 9

    // which is equivalent to
    a * c + b * c // 9

## 规范

Specification | Status | Comment
--- | --- | ---
ECMAScript Latest Draft (ECMA-262) The Grouping Operator | Draft |
ECMAScript 2015 (6th Edition, ECMA-262) The Grouping Operator | Standard |
ECMAScript 5.1 (ECMA-262) The Grouping Operator | Standard |
ECMAScript 1st Edition (ECMA-262) The Grouping Operator | Standard | 初始化定义.在JavaScript1.0中生效

## 浏览器兼容性

本页的浏览器兼容性表都是基于结构数据，如果你想更新数据.可以查看 https://github.com/mdn/browser-compat-data 并且请给我们发送合并请求.

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
Grouping operator `()` | 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

- 运算符优先级
- `delete`
- `typeof`