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Math.abs

The Math.abs() function returns the absolute value of a number, that is

Math.abs(x)=|x|={xifx>00ifx=0-xifx<0{\mathtt{\operatorname{Math.abs}(x)}} = {|x|} = \begin{cases} x & \text{if} \quad x \geq 0 \\ -x & \text{if} \quad x < 0 \end{cases}

Syntax

Math.abs(x)

Parameters

x
A number.

Return value

The absolute value of the given number.

Description

Because abs() is a static method of Math, you always use it as Math.abs(), rather than as a method of a Math object you created (Math is not a constructor).

Examples

Behavior of Math.abs()

Passing an empty object, an array with more than one member, a non-numeric string or undefined/empty variable returns NaN. Passing null, an empty string or an empty array returns 0.

Math.abs('-1');     // 1
Math.abs(-2);       // 2
Math.abs(null);     // 0
Math.abs('');       // 0
Math.abs([]);       // 0
Math.abs([2]);      // 2
Math.abs([1,2]);    // NaN
Math.abs({});       // NaN
Math.abs('string'); // NaN
Math.abs();         // NaN

Specifications

Specification Status Comment
ECMAScript 1st Edition (ECMA-262) Standard Initial definition. Implemented in JavaScript 1.0.
ECMAScript 5.1 (ECMA-262)
The definition of 'Math.abs' in that specification.
Standard
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Math.abs' in that specification.
Standard
ECMAScript 2017 Draft (ECMA-262)
The definition of 'Math.abs' in that specification.
Draft

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) (Yes) (Yes) (Yes) (Yes)
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

See also

© 2005–2017 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/abs