A value representing Not-A-Number.

Core property

Syntax

Description

NaN is a top-level property and is not associated with any object.

The initial value of NaN is NaN.

NaN is always unequal to any other number, including NaN itself; you cannot check for the not-a-number value by comparing to Number.NaN. Use the isNaN function instead.

Several MetaScript methods (such as the Number constructor, parseFloat, and parseInt) return NaN if the value specified in the parameter is not a number.
You might use the NaN property to indicate an error condition for a function that should return a valid number.

See also

isNaN, Number.NaN