What is NaN Function in Javascript?

Not a number ,which used in client side to check input is number or not

NaN is Not a Number , which is used for identifying that a variable is a number or not ? This function returns true if the value is NaN, and false if not.

NaN refers to Not a Number , which is used for identifying wether a variable is having a number or not ?

most of the time NaN is used whether the given value is number or not

that is 'Not a Number' it is use to check the given value is number or not

It simply means the input you enter NaN(Not a Number)

The isNaN() function determines whether a value is an illegal number (Not-a-Number). This function returns true if the value is NaN, and false if not. E.g.:- var a = isNaN(123) Out:-false and var e = isNaN("Hello") Out:- true

Check whether a number is an illegal number or not... Example: 1) var A1 = isNaN(523) .....output:false 2) var B1 = isNaN("12").....output :true