Bitwise OR (|)

The bitwise OR operator (|) returns a 1 in each bit position for which the corresponding bits of either or both operands are 1s.


a | b


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 OR operation is:

a b a OR b
0 0 0
0 1 1
1 0 1
1 1 1
.    9 (base 10) = 00000000000000000000000000001001 (base 2)
    14 (base 10) = 00000000000000000000000000001110 (base 2)
14 | 9 (base 10) = 00000000000000000000000000001111 (base 2) = 15 (base 10)

Bitwise ORing any number x with 0 yields x.


Using bitwise OR

// 9  (00000000000000000000000000001001)
// 14 (00000000000000000000000000001110)

14 | 9; 
// 15 (00000000000000000000000000001111)


ECMAScript (ECMA-262)
The definition of 'Bitwise OR expression' in that specification.

Browser compatibility

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ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
Bitwise OR (a | b)Chrome Full support 1Edge Full support 12Firefox Full support 1IE Full support 3Opera Full support 3Safari Full support 1WebView Android Full support 1Chrome Android Full support 18Firefox Android Full support 4Opera Android Full support 10.1Safari iOS Full support 1Samsung Internet Android Full support 1.0nodejs Full support 0.1.100


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See also