Leap Year Checking

Index(Leap-Year).js

//Leap year

function leapYear(year){
  if ( year % 4  == 0 ){
      if( year % 100 == 0){
          if( year % 400 == 0 ){
              return "IS Leap Year";
          } else {
              return"NOT Leap Year";
          }
      }else{
          return "IS Leap Year";
      }
  }else{
      return "NOT Leap Year";
  }
}

var a = prompt("Enter the year you want to know");

alert ( leapYear( a ) );