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Increment

The increment operator (++) increments (adds one to) its operand and returns a value.

Syntax

Operator: x++ or ++x

Description

If used postfix, with operator after operand (for example, x++), the increment operator increments and returns the value before incrementing.

If used prefix, with operator before operand (for example, ++x), the increment operator increments and returns the value after incrementing.

Examples

Postfix increment

let x = 3;
y = x++;

// y = 3
// x = 4

Prefix increment

let a = 2;
b = ++a;

// a = 3
// b = 3

Specifications

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
Increment (++) 2 12 1 3 3 4
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
Increment (++) 1 18 4 10.1 3.2 1.0
Server
Node.js
Increment (++) 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/Increment