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("123") + "<br>";
var f = isFinite("Hello") + "<br>";
var
g = isFinite("2005/12/12");
var res = a + b + c + d + e + f + g;
The result of res will be:
true
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
| Function | |||||
|---|---|---|---|---|---|
| isFinite() | Yes | Yes | Yes | Yes | Yes |
Syntax
isFinite(value)
Parameter Values
| Parameter | Description |
|---|---|
| value | Required. The value to be tested |
Technical Details
| Return Value: | A Boolean. Returns false if the value is +infinity, -infinity, or NaN, otherwise it returns true. |
|---|---|
| JavaScript Version: | 1.3 |
< JavaScript Global Functions