Using ES6 generators for prime number generation:

function isPrime(n) {
  if (isNaN(n) || !isFinite(n) || n % 1 || n < 2) return false;
  var m = Math.sqrt(n);
  for (var i = 2; i <= m; i++) {
    if (n % i == 0) return false;
  }
  return true;
}

function* genPrime() {
  var count = 0;
  while (1) {
    if (isPrime(count)) yield count;
    count++;
  }
}

Now, keep generating them!
javascript
var meh = genPrime();

while (1) {
  console.log(meh.next().value);
}

BTW, one more interesting read on sieves with generators.