The left shift operator (<<
) shifts the first operand the specified number of bits to the left. Excess bits shifted off to the left are discarded. Zero bits are shifted in from the right.
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Syntax
a << b
Description
This operator shifts the first operand the specified number of bits to the left. Excess bits shifted off to the left are discarded. Zero bits are shifted in from the right.
For example, 9 << 2
yields 36:
. 9 (base 10): 00000000000000000000000000001001 (base 2) -------------------------------- 9 << 2 (base 10): 00000000000000000000000000100100 (base 2) = 36 (base 10)
Bitwise shifting any number x
to the left by y
bits yields x * 2 ** y
.
So e.g.: 9 << 3
translates to: 9 * (2 ** 3) = 9 * (8) = 72
.
Examples
Using left shift
9 << 3; // 72 // 9 * (2 ** 3) = 9 * (8) = 72
Specifications
Specification |
---|
ECMAScript (ECMA-262) The definition of 'Bitwise Shift Operators' in that specification. |
Browser compatibility
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.
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Bitwise left shift (a << b ) | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 3 | Opera Full support 3 | Safari Full support 1 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
Legend
- Full support
- Full support