| Core function | |
| Implemented in |
Navigator 2.0: Unix only Navigator 3.0, LiveWire 1.0: all platforms |
Syntax
isNaN(testValue)
Parameters
testValue | The value you want to evaluate. |
Description
isNaN is a built-in JavaScript function. It is not a method associated with any object, but is part of the language itself.
On platforms that support NaN, the parseFloat and parseInt functions return "NaN" when they evaluate a value that is not a number. isNaN returns true if passed "NaN", and false otherwise.
Examples
The following example evaluates floatValue to determine if it is a number and then calls a procedure accordingly:
floatValue=parseFloat(toFloat)
if (isNaN(floatValue)) {
notFloat()
} else {
isFloat()
} See also
Number.NaN, parseFloat, parseInt
Last Updated: 10/31/97 16:38:00