Core JavaScript 1.5 Reference:Global Properties:NaN
From MDC
(Redirected from Core JavaScript 1.5 Reference:Properties:NaN)
Contents |
[edit] Summary
A value representing Not-A-Number.
| Core Global Property | |
| Implemented in: | JavaScript 1.3 |
| ECMA Version: | ECMA-262 |
[edit] Syntax
NaN
[edit] Description
NaN is a property of the global object, i.e. it is a variable in global scope.
The initial value of NaN is Not-A-Number - the same as the value of Number.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 JavaScript methods (such as the Number constructor, parseFloat, and parseInt) return NaN if the value specified in the parameter can not be parsed as a number.
You might use the NaN property to indicate an error condition for your function that returns a number in case of success.
JavaScript prints the value Number.NaN as NaN.