primes.js

isPrime = function(x){
  // if number is 1 , 0 or negative it is not a prime 
  if(x <= 1) return false; 
  if(x == 2) return true ;
  for( var i = x - 1 ; i > 1 ; i-- ){
    console.log(x + ' % ' + i + " " + x % i );
    if(x % i == 0) return false;
  }
  return true;
}


var find_next_prime= function(n){
  var i = n + 1;
  while(!isPrime(i)){
    i++;
  }
  return i;
}