An example of optimization of Javascript loop

//
// Finding divisors in Javascript
// An example of optimization of Javascript loop
//


// this runs in 1317 ms for n=1E8
function divisors_count_slow ( n ) {// 1E8 -> 1317ms
  if (n == 1) return 1;
  i = 1;
  count = 0;
  p = 0;
  n2 = n/2;
  while (i < n2 + 1 && p != i) {
    d = n / i;
    if (d % 1.0 == 0) {
      count+=2;
      p = d;
    }
    i++;
  }
  return count;
}

// runs in 1246 ms for n=1E8
function divisors_count_faster ( n ) {
  if (n == 1) return 1;
  i = 1;
  count = 0;
  p = 0;
  while (i < n / 2 + 1 && p != i) {
    d = n / i;
    if (d % 1.0 == 0) {
      count+=2;
      p = d;
    }
    i++;
  }
  return count;
}

// this runs in 580 ms for n=1E8
function divisors_count (n) {
  if (n == 1) return 1;
  i = 1;
  count = 0;
  p = 0;
  while (i < n / 2 + 1 && p != i) {
    d = n % i;
    if (d == 0) {
      count+=2;
      p = n/i;
    }
    i++;
  }
  return count;
}