The JavaScript isNaN() Function is used to check whether a given value is an illegal number or not. It returns true if the value is a NaN else returns false. It is different from the Number.isNaN() Method.
Syntax:
isNaN( value )
Parameter Values: This method accepts a single parameter as mentioned above and described below:
- value: It is a required value passed in the isNaN() function.
Return Value: It returns a Boolean value i.e. returns true if the value is NaN else returns false.
Example: In this example, we will check various values for isNan() and the output will be in boolean format.
Javascript
<script> console.log(isNaN(12)); console.log(isNaN(0 / 0)); console.log(isNaN(12.3)); console.log(isNaN("Geeks")); console.log(isNaN("13/12/2020")); console.log(isNaN(-46)); console.log(isNaN(NaN)); </script> |
Output:
false true false true true false true
We have a complete list of Javascript Function methods, to check those please go through this Javascript Function Complete reference article.
Supported Browsers:
- Chrome 1 and above
- Firefox 1 and above
- Edge 12 and above
- Opera 3 and above
- Safari 1 and above
We have a Cheat Sheet on Javascript where we covered all the important topics of Javascript to check those please go through Javascript Cheat Sheet-A Basic guide to JavaScript.
