24.127. NaN: the not-a-number propertyECMAScript v124.127.1. SynopsisNaN 24.127.2. DescriptionNaN is a 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( ), because NaN always compares as nonequal to any other value, including itself! 24.127.3. See AlsoInfinity, isNaN( ), Number.NaN |