JavaScript isFinite() function

Definition and usage

isFinite() The function can determine whether a number is a finite valid number.

If the value is +infinity, -infinity, or NaN (not a number), this function returns false, otherwise it returns true.

Example

Check if the number is a finite valid number:

var a = isFinite(123) + "<br>";
var b = isFinite(-1.23) + "<br>";
var c = isFinite(5-2) + "<br>";
var d = isFinite(0) + "<br>";
var e = isFinite("123") + "<br>";
var f = isFinite("Hello") + "<br>";
var g = isFinite("2005/12/12");
var res = a + b + c + d + e + f + g;

Try it yourself

Syntax

isFinite(value)

Parameter value

Parameter Description
value Required. The value to be tested.

Technical details

Return value: Boolean value. If the value is +infinity, -infinity, or NaN, it returns false, otherwise it returns true.
Versión de JavaScript: ECMAScript 1

Compatibilidad del navegador

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