确保字符串的每个单词首字母都大写，其余部分小写。

function titleCase(str) {
  var aa = str.toLowerCase();
  var arr = aa.split(" ");
  var array = [];
  for (var i in arr) {
    cc = arr[i].replace(/^\S/, arr[i][0].toUpperCase());
    array.push(cc);
  }
  
  return array.join(" ");
}

titleCase("I'm a little tea pot");

　　

titleCase("I'm a little tea pot") 应该返回一个字符串

 

titleCase("I'm a little tea pot") 应该返回 "I'm A Little Tea Pot".

 

titleCase("sHoRt AnD sToUt") 应该返回 "Short And Stout".

 

titleCase("HERE IS MY HANDLE HERE IS MY SPOUT") 应该返回 "Here Is My Handle Here Is My Spout".