isNaN Method (JScript 5.6)


isNaN(numValue)

true if the value converted to the Number type is the NaN, otherwise false.

The required numValue is the value to be tested against NAN.

You typically use this method to test return values from the parseInt and parseFloat methods.

Alternatively, a variable could be compared to itself. If it compares as unequal, it is NaN. This is because NaN is the only value that is not equal to itself.

Version 1

Applies To: Global Object (JScript 5.6)

┬á	Copy Code
isNaN(100); //Returns false isNaN("100"); //Returns false isNaN("ABC"); //Returns true isNaN("10C"); //Returns true isNaN(Math.sqrt(-1)); //Returns true

Reference

isFinite Method (JScript 5.6)
NaN Property (Global) (JScript 5.6)
parseFloat Method (JScript 5.6)
parseInt Method (JScript 5.6)

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Requirements

Example

See Also

Reference