[j0hnik]

function generate(arr, n){
  var length = arr.length, x=0;
      result = new Array(Math.pow(length, n));

  for(var i = result.length, temp = new Array(n), j; i--;){
    j = n;

    while(j--){
      temp[j] = arr[i / Math.pow(length, j) % length | 0];
      x++;
    }

  }
  
  return x;
}
alert(generate(['A','B','C','D','E'], 4));