NaN : Not A Number
It is a returned value
It is not configurable and not writable.
Example of NaN
When we will get output as NaN ?<script>
var a = 'xyz';
document.write(a*2); // Output NaN
</script>Not equal to itself
NaN is the only JavaScript value which is not equal to itself.<script>
var a = NaN;
if(a === a){
document.write('Equal')
}else{
document.write('Not Equal')
}
</script>To check the value is NaN, we can use isNaN
User entered data from an input text box is always a string, so for any mathematical calculation we need to convert them to number by using parseFlot or parseInt. Otherwise we will get NaN as output of any mathematical calculation if we use directly these inputs.
String to Number by parseInt
JavaScript Math Reference
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Math Functions in JavaScript
Math Functions Math Constants used JavaScript random() function to generate random numbersround() function to get rounded value of a numberIsNaN() function to check data if number or notceil() function to get just next higher integerfloor() function to get just highest lower integertoFixed() function to format decimal places of a numbertoPrecision() function to fix the places of a numberparseFloat() function to convert string to floating numberparseInt() function to convert string to numbermodulus % to get the reminder of a divisionpow to get the power of an integermax to get the highest integer from a set of numberabs to get the absolute value from any integersqrt to get square root of any numberlog to get the log value of numberexp to get E to the power of XMath conversion from one base to other for number systemMath conversion Decimal to Hexadecimal number system