JavaScript isNaN() Function
 JavaScript Functions
Definition and Usage
The isNaN() function is used to check if a value is not a legal number, NaN
(Not-a-Number).
Syntax
| Parameter |
Description |
| value |
Required. The value to be tested |
Example
Example
Check for NaN values:
<script type="text/javascript">
document.write(isNaN(123)+ "<br />");
document.write(isNaN(-1.23)+ "<br />");
document.write(isNaN(5-2)+ "<br />");
document.write(isNaN(0)+ "<br />");
document.write(isNaN("Hello")+ "<br />");
document.write(isNaN("2005/12/12")+ "<br />");
</script>
|
The output of the code above will be:
false
false
false
false
true
true
|
Try it yourself »
|
JavaScript Functions
 |
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