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JavaScript isFinite() Function

Function Reference JavaScript Global Functions

Example

Check whether a number is a finite, legal 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("Hello") + "<br>";
var f = isFinite("2005/12/12") + "<br>";

var res = a + b + c + d + e + f;

The result of res will be:

true
true
true
true
false
false

Try it yourself »

Definition and Usage

The isFinite() function determines whether a number is a finite, legal number.

This function returns false if the value is +infinity, -infinity, or NaN (Not-a-Number), otherwise it returns true.


Browser Support

Internet Explorer Firefox Opera Google Chrome Safari

The isFinite() function is supported in all major browsers.


Syntax

isFinite(value)

Parameter Values

Parameter Description
value Required. The value to be tested

Return Value

Type Description
Boolean Returns "false" if the value is +infinity, -infinity, or NaN, otherwise it returns true.

Technical Details

JavaScript Version: 1.3


Function Reference JavaScript Global Functions

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