isFinite()

Summary

The global isFinite() function determines whether the passed value is a finite number. If needed, the parameter is first converted to a number.

Syntax

isFinite(testValue)

Parameters

testValue
The value to be tested for finiteness.

Description

isFinite is a top-level function and is not associated with any object.

You can use this function to determine whether a number is a finite number. The isFinite function examines the number in its argument. If the argument is NaN, positive infinity, or negative infinity, this method returns false; otherwise, it returns true.

Examples

isFinite(Infinity);  // false
isFinite(NaN);       // false
isFinite(-Infinity); // false

isFinite(0);         // true
isFinite(2e64);      // true


isFinite("0");       // true, would've been false with the more robust Number.isFinite("0")

Specifications

Specification Status Comment
ECMAScript 2nd Edition. Standard Initial definition.
ECMAScript Language Specification 5.1th Edition (ECMA-262) Standard  
ECMAScript Language Specification 6th Edition (ECMA-262) 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

Document Tags and Contributors

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Contributors to this page: evilpie, Sheppy, fscholz, XP1, Brettz9, orduh, Mgjbot, Ptak82, Sarabjot, Maian, Dria
Last updated by: orduh,