isPrime.js

function isPrimeNumber(n) {
  for (var i = 2; i < n; i++) { // i will always be less than the parameter so the condition below will never allow parameter to be divisible by itself ex. (7 % 7 = 0) which would return true
    if (n % i === 0) return false // when parameter is divisible by i, it's not a prime number so return false
  }
  return n > 1 // otherwise it's a prime number so return true (it also must be greater than 1, reason for the n > 1 instead of true)
}