Availability

JavaScript 1.3; JScript 3.0; ECMAScript v1

Synopsis

NaN 

Description

NaN is global property that refers to the special numeric not-a-number value. The NaN property is not enumerated by for/in loops and cannot be deleted with the delete operator. Note that NaN is not a constant and can be set to any other value, something that you should take care not to do.

To determine if a value is not a number, use isNaN( ), since NaN always compares non-equal to any other value, including itself!

See Also

Infinity, isNaN( ), Number.NaN