The global isFinite()
function determines whether the passed value is a finite number. If needed, the parameter is first converted to a number.
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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
or undefined
; 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
Using isFinite
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 |
---|
ECMAScript (ECMA-262) The definition of 'isFinite' in that specification. |
Browser compatibility
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
isFinite | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 4 | 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