# JavaScript Number.isNaN() Method

• Last Updated : 04 Sep, 2020

Below is the example of the Number.isNaN() Method.

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• Example:
 `<``script``>``function GFGFun() {``  ``var res = "";``  ``res = res + Number.isNaN(123);``document.write(res);  `` ` `}``GFGFun();```
• Output:
`false`

The Number.isNan method in JavaScript is used to determines whether the passed value is NaN(Not a Number) and is of the type “Number”.
In JavaScript, the value NaN is considered a type of number.

Syntax:

`Number.isNaN(value)`

Parameters Used:
1. Value :It is the value which is to be tested for NaN.

Return Value:
The Number.isNaN() method in JavaScript returns true if the passed value is Nan and is of the type number,else it returns false.

Examples:

```Input : 0/0
Output : true

Input : 213
Output : false

Input : '213'
Output : false

Input : 'hello'
Output : false

Input : NaN
Output : true

```
1. When an equation resulting in infinite value is passed as a parameter.
 `<``script``>``function GFGFun() {``  ``var res = "";``  ``res = res + Number.isNaN(0/0);``document.write(res);  `` ` `}``GFGFun();```

Output:

`Output : true`
2. When a number is passed as a parameter.
 `<``script``>``function GFGFun() {``  ``var res = "";``  ``res = res + Number.isNaN(321);``document.write(res);  `` ` `}``GFGFun();```

Output:

`Output : false`
3. When a number in string representation is passed as a parameter.
 `<``script``>``function GFGFun() {``  ``var res = "";``  ``res = res + Number.isNaN(213);``document.write(res);  `` ` `}``GFGFun();```

Output:

`Output : false`
4. When a string is passed as a parameter.
 `<``script``>``function GFGFun() {``  ``var res = "";``  ``res = res + Number.isNaN("hello");``document.write(res);  `` ` `}``GFGFun();```

Output:

`Output : false`
5. When Nan is passed as a parameter.
 `<``script``>``function GFGFun() {``  ``var res = "";``  ``res = res + Number.isNaN(NaN);``document.write(res);  `` ` `}``GFGFun();```

Output:

`Output : true`

Supported Browsers: