Microsoft® JScript™ isNaN Method | Language Reference Version 1

See Also Applies To

##### Description

> Determines whether a value is the reserved value NaN (not a number).

##### Syntax

> isNaN(numvalue)

> The numvalue argument is the value to be tested against NaN.

##### Remarks

> The isNaN function returns true if the value is NaN, and false otherwise. You typically use this function 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.

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