按位与(&)
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
按位与(&
)运算符在两个操作数对应的二进位都为 1
时,该位的结果值才为 1
。
尝试一下
const a = 5; // 00000000000000000000000000000101
const b = 3; // 00000000000000000000000000000011
console.log(a & b); // 00000000000000000000000000000001
// Expected output: 1
语法
js
a & b
描述
操作数被转换为 32 位整数,并由一系列位(0 和 1)表示。超过 32 位的数字将丢弃其最高有效位。例如,以下大于 32 位的整数将被转换为 32 位整数:
Before: 11100110111110100000000000000110000000000001 After: 10100000000000000110000000000001
第一个操作数中的每个位都与第二个操作数中的相应位配对:第一位到第一位,第二位到第二位,依此类推。
将运算符应用于每对位,然后按位构造结果。
与运算的真值表:
a | b | a AND b |
---|---|---|
0 | 0 | 0 |
0 | 1 | 0 |
1 | 0 | 0 |
1 | 1 | 1 |
9 (base 10) = 00000000000000000000000000001001 (base 2) 14 (base 10) = 00000000000000000000000000001110 (base 2) -------------------------------- 14 & 9 (base 10) = 00000000000000000000000000001000 (base 2) = 8 (base 10)
任何数字 x
与 0
进行按位与运算都会得到 0
。
示例
使用按位与
js
// 5: 00000000000000000000000000000101
// 2: 00000000000000000000000000000010
5 & 2; // 0
规范
Specification |
---|
ECMAScript® 2025 Language Specification # prod-BitwiseANDExpression |
浏览器兼容性
Report problems with this compatibility data on GitHubdesktop | mobile | server | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Bitwise AND ( a & b ) |
Legend
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- Full support
- Full support
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.