JavaScript isFinite()Function
JavaScript Global FunctionsDefinition and Usage
The isFinite() function is used to check whether its argument is infinite, or in other words, whether it is a finite number.
Tip:If the argument is NaN, positive infinity, or negative infinity, it returns false; otherwise, it returns true.
Syntax
isFinite(value)
| Parameter | Description |
|---|---|
| value | Required. The number to be tested. |
Browser Support
| Function | |||||
|---|---|---|---|---|---|
| isFinite() | Yes | Yes | Yes | Yes | Yes |
Example
Example
Use isFinite() to detect infinite numbers:
document.write(isFinite(123)+ "<br>");
document.write(isFinite(-1.23)+ "<br>");
document.write(isFinite(5-2)+ "<br>");
document.write(isFinite(0)+ "<br>");
document.write(isFinite("Hello")+ "<br>");
document.write(isFinite("2005/12/12")+ "<br>");
The output of the above example is:
true
true
true
true
false
false
true
true
true
false
false
Try it yourself »
More examples:
Example
isFinite(Infinity); // false
isFinite(NaN); // false
isFinite(-Infinity); // false
isFinite(0); // true
isFinite(2e64); //true, but with the more robust Number.isFinite(null) you will get false
isFinite("0"); //true, but with the more robust Number.isFinite('0') you will get false
Other Extensions