is nan javascript code example

Example 1: compare NaN in javascript if condititon

// Use isNaN() 
// In javascript compare NaN direct alweys return false
let num1 = Number("Vishal");

// This code never work
if(num1 == NaN){  // Direct compare NaN alweys return false so use isNaN() function
  ....... Your Code .......
}  

// This code work
if(isNaN(num1){
  .........Your Code .......
}

Example 2: nan javascript

// NaN:  Not a Number in javascript
console.log(parseInt('1.23'));				// 1.23
console.log(parseInt('something'));			// NaN

Example 3: isnan in javascript

var s = userInput[0];
  if(isNaN(s) !== true)
  {
      console.log("yes");
  }
  else
  {
      console.log("no");
  }

Example 4: javascript check if is nan

function isNaN(x) {
   return x !== x;
};
isNaN(NaN);//true

Example 5: javascript nan

NaN = Not a number.

Example 6: nan in js

var val = Number.NaN;