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.
Return value
false
if the argument is positive or negative Infinity
or NaN
; otherwise, true
.
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(910); // true isFinite(null); // true, would've been false with the // more robust Number.isFinite(null) isFinite('0'); // true, would've been false with the // more robust Number.isFinite("0")
Specifications
Specification | Status | Comment |
---|---|---|
ECMAScript 3rd Edition (ECMA-262) | Standard | Initial definition. |
ECMAScript 5.1 (ECMA-262) The definition of 'isFinite' in that specification. |
Standard | |
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'isFinite' in that specification. |
Standard | |
ECMAScript Latest Draft (ECMA-262) The definition of 'isFinite' in that specification. |
Living Standard |
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.
Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|---|
Basic support | Yes | Yes | Yes | Yes | Yes | Yes |
Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | IE mobile | Opera Android | iOS Safari |
---|---|---|---|---|---|---|---|
Basic support | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
See also
Document Tags and Contributors
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Last updated by:
schalkneethling,