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Bitwise AND

The bitwise AND operator (&) returns a 1 in each bit position for which the corresponding bits of both operands are 1s.

Syntax

a & b

Description

The operands are converted to 32-bit integers and expressed by a series of bits (zeroes and ones). Numbers with more than 32 bits get their most significant bits discarded. For example, the following integer with more than 32 bits will be converted to a 32 bit integer:

Before: 11100110111110100000000000000110000000000001
After:              10100000000000000110000000000001

Each bit in the first operand is paired with the corresponding bit in the second operand: first bit to first bit, second bit to second bit, and so on.

The operator is applied to each pair of bits, and the result is constructed bitwise.

The truth table for the AND operation is:

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)

Bitwise ANDing any number x with 0 yields 0.

Examples

Using bitwise AND

// 5: 00000000000000000000000000000101
// 2: 00000000000000000000000000000010
5 & 2; // 0

Specifications

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
Bitwise AND (a & b) 1 12 1 3 3 1
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
Bitwise AND (a & b) 1 18 4 10.1 1 1.0
Server
Node.js
Bitwise AND (a & b) 0.1.100

See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://wiki.developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Bitwise_AND