function str_split (string, split_length) {
  // http://kevin.vanzonneveld.net
  // +     original by: Martijn Wieringa
  // +     improved by: Brett Zamir (http://brett-zamir.me)
  // +     bugfixed by: Onno Marsman
  // +      revised by: Theriault
  // +        input by: Bjorn Roesbeke (http://www.bjornroesbeke.be/)
  // +      revised by: Rafał Kukawski (http://blog.kukawski.pl/)
  // *       example 1: str_split('Hello Friend', 3);
  // *       returns 1: ['Hel', 'lo ', 'Fri', 'end']
  if (split_length === null) {
    split_length = 1;
  }
  if (string === null || split_length < 1) {
    return false;
  }
  string += '';
  var chunks = [],
    pos = 0,
    len = string.length;
  while (pos < len) {
    chunks.push(string.slice(pos, pos += split_length));
  }

  return chunks;
}

str_split('Hello Friend', 3);

['Hel', 'lo ', 'Fri', 'end']