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How to analyze NaN and isNaN in js? aiming at this problem, this article introduces the corresponding analysis and solution in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible method.

NaN and isNaN of js

NaN "Not a Number". The occurrence of this number is so rare that we can ignore it. When the operation cannot return the correct value, the "NaN" value is returned. The NaN value is very special because it is "not a number", so any number is not equal to it, and even NaN itself is not equal to NaN.

IsNaN

Calculate a parameter and check whether it is a numeric value.

Core function implementation version Navigator 2.0: Navigator 3.0 on Unix only, LiveWire 1.0: all platforms

Syntax isNaN (testValue) parameter

TestValue the value you want to test.

Describes isNaN as a built-in JavaScript function. It is not a method associated with any object, but only a part of the language.

On platforms that support NaN, the parseFloat and parseInt functions will return "NaN" when calculating a value that is not a numeric value. IsNaN returns true if the passed parameter is "NaN", otherwise it returns false.

The following example calculates floatValue to determine whether it is a numeric value so that the appropriate procedure can be called:

FloatValue=parseFloat (toFloat)

If (isNaN (floatValue)) {

NotFloat ()

} else {

IsFloat ()

}

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