Bonfire: Title Case a Sentence

function titleCase(str){
  str = str.toLowerCase().split(' ');
  /*
    str = str.toLowerCase();
    str = str.split(' ');
  */
  for(var i = 0; i < str.length; i++){
    var cF = str[i].charAt(0);
    str[i] = str[i].replace(cF, cF.toUpperCase());
  }
    return str.join(' ');
}
titleCase("I'm a little tea pot", "");