JavaScript » Constants » NaN
NaN means "Not-a-Number". It is used to signify that a value is not a legal number.
In ECMAScript, NaN is classified as a primitive value.
NaN means "Not-a-Number". It is used to signify that a value is
not a legal number.
Note that the primitive value, Infinity, is used to signify that a
number, 1.5x10321 for example, has exceeded the defined range of
legal values for a floating point number in JavaScript.
You can use the
isNan function to test a value to
see if it is NaN.
