JavaScript isNaN() Function
 Complete Function Reference
Definition and Usage
The isNaN() function is used to check if a value is not a number.
Syntax
| Parameter |
Description |
| number |
Required. The value to be tested |
Example
In this example we use isNaN() to check some 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 Demos
isNaN()
How to use isNaN().
Complete Function Reference
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