JavaScript » Functions » isNaN
- Syntax:
- isNaN(testvalue)
The isNaN function is used to determine if the argument, testvalue, is a NaN.
A NaN, which means "Not-a-Number", is classified as a primitive value by the ECMA-262 standard and indicates that the specified value is not a legal number. The function returns true if the argument is not a number and false if the argument is a number.
Examples
Code:
document.write(isNaN("Ima String"))
document.write(isNaN(0/0))
document.write(isNaN("348"))
document.write(isNaN(348))Output:
true
true
false
falseExplanation:
The classic example of a NaN is zero divided by zero, 0/0.
