如何使用JavaScript大写字符串中单词的第一个字母

Question

我正在尝试使用javascript将句子中的单词大写。例如

var input = "I am not bad with javascript."
var output = "I Am Not Bad With Javascript."

我有以下代码，但我不明白为什么我的替换代码不能工作。谢谢

var loop = function(collection, callback){
    // ultimate side-effects function
    for (var i = 0; i < collection.length; i++){
      callback(collection[i]);
    }
};

    var capitalizeFirstLetters = function(string) {
      // have a new string
      // split the string into substring
      // use the loop function to find the "space"and CAP letter after 
      var newString = [];
      var subString = string.split(' ');
      loop(subString, function(word){
        subString.replace(word[0], word[0].toUpperCase());
        return newString.push(subString);
      })
      return newString.join(' ');
    }

Answer 1

在这里这应该是可行的

​

function titleCase(str) {
   var splitStr = str.toLowerCase().split(' ');
   for (var i = 0; i < splitStr.length; i++) {
       // You do not need to check if i is larger than splitStr length, as your for does that for you
       // Assign it back to the array
       splitStr[i] = splitStr[i].charAt(0).toUpperCase() + splitStr[i].substring(1);     
   }
   // Directly return the joined string
   return splitStr.join(' '); 
}

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

​

Answer 2

您可以尝试如下所示：

var input = "I am not bad with javascript."
input = input.split(" ")
             .map(function(item){
                 return item[0].toUpper()+item.slice(1);
             })
             .join(" ");

​

var input = "I am not bad with javascript."
input = input.split(" ")
             .map(function(item){
                 return item[0].toUpperCase()+item.slice(1);
             }).join(" ");
alert(input);

​