也是一个很好的选择(特别是如果你使用freeCodeCamp):

function titleCase(str) {
  var wordsArray = str.toLowerCase().split(/\s+/);
  var upperCased = wordsArray.map(function(word) {
    return word.charAt(0).toUpperCase() + word.substr(1);
  });
  return upperCased.join(" ");
}

这是一个简单的转换方法，可以传递一个值来获得所需的输出。

String.prototype.toChangeCase = function (type) {
    switch (type) {
        case 'upper-first':
            return this.charAt(0).toUpperCase() + this.substr(1).toLowerCase();
        case 'upper-each':
            return this.split(' ').map(word => {
                return word.charAt(0).toUpperCase() + word.substr(1).toLowerCase();
            }).join(' ');
        default:
            throw Error(`In order to get the output pass a value 'upper-first', 'upper-each'`);
    }
}

输出

"capitalize first Letter of Each word in a Sstring".toChangeCase('upper-first')
"Capitalize first letter of each word in a sstring"


"capitalize first Letter of Each word in a Sstring".toChangeCase('upper-each')
"Capitalize First Letter Of Each Word In A Sstring"

"Capitalize First Letter Of Each Word In A String".toChangeCase()
VM380:12 Uncaught Error: In order to get the output pass a value 'upper-first', 'upper-each'
    at String.toChangeCase (<anonymous>:12:19)
    at <anonymous>:16:52

ES6让

const captilizeAllWords = (sentence) => {
  if (typeof sentence !== "string") return sentence;
  return sentence.split(' ')
    .map(word => word.charAt(0).toUpperCase() + word.slice(1))
    .join(' ');
}


captilizeAllWords('Something is going on here')

用奇数分隔符将字符串中的每个单词大写(不使用正则表达式的快速解决方案)

function capitalizeFirstLetter(str) {
  function isLetter(char) {
    const code = char.charCodeAt(0);
    // Considering apostrophe (char code 39) as a letter
    return code > 64 && code < 91 || code > 96 && code < 123 || char.charCodeAt(0) === 39;
  }

  str = str.toLowerCase();

  let newStr = '';
  let processingWord = false;

  for (let i = 0; i < str.length; i += 1) {
    if (!processingWord && isLetter(str[i])) {
      processingWord = true;
      newStr += str[i].toUpperCase();
    }
    else {
      newStr += str[i];
    }

    if (processingWord && !isLetter(str[i])) {
      processingWord = false;
    }
  }

  return newStr;
}

// stack overflow -> Stack Overflow
// ping-pong -> Ping-Pong
// domino's pizza -> Domino's Pizza
// /some/path -> /Some/Path

下面是字符串中每个单词首字母大写的另一种方法。

使用prototype为String对象创建一个自定义方法。

String.prototype.capitalize = function() {
    var c = '';
    var s = this.split(' ');
    for (var i = 0; i < s.length; i++) {
        c+= s[i].charAt(0).toUpperCase() + s[i].slice(1) + ' ';
    }
    return c;
}
var name = "john doe";
document.write(name.capitalize());

或者可以使用replace()，将每个单词的第一个字母替换为“大写”。

function titleCase(str) {
    return str.toLowerCase().split(' ').map(function(word) {
               return word.replace(word[0], word[0].toUpperCase());
           }).join(' ');
}

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