更简单的高性能版本，具有简单的缓存。

var TITLE_CASE_LOWER_MAP = { 'a': 1, 'an': 1, 'and': 1, 'as': 1, 'at': 1, 'but': 1, 'by': 1, 'en':1, 'with': 1, 'for': 1, 'if': 1, 'in': 1, 'of': 1, 'on': 1, 'the': 1, 'to': 1, 'via': 1 }; // LEAK/CACHE TODO: evaluate using LRU. var TITLE_CASE_CACHE = new Object(); toTitleCase: function (title) { if (!title) return null; var result = TITLE_CASE_CACHE[title]; if (result) { return result; } result = ""; var split = title.toLowerCase().split(" "); for (var i=0; i < split.length; i++) { if (i > 0) { result += " "; } var word = split[i]; if (i == 0 || TITLE_CASE_LOWER_MAP[word] != 1) { word = word.substr(0,1).toUpperCase() + word.substr(1); } result += word; } TITLE_CASE_CACHE[title] = result; return result; },

约翰·史密斯->约翰·史密斯

'john smith'.replace(/(^\w|\s+\w){1}/g, function(str){ return str.toUpperCase() } );

ES-6 way to get title case of a word or entire line.
ex. input = 'hEllo' --> result = 'Hello'
ex. input = 'heLLo woRLd' --> result = 'Hello World'

const getTitleCase = (str) => {
  if(str.toLowerCase().indexOf(' ') > 0) {
    return str.toLowerCase().split(' ').map((word) => {
      return word.replace(word[0], word[0].toUpperCase());
    }).join(' ');
  }
  else {
    return str.slice(0, 1).toUpperCase() + str.slice(1).toLowerCase();
  }
}

这个解决方案将标点符号考虑到新句子中，处理引用，将小词转换为小写，忽略首字母缩写或全大写单词。

var stopWordsArray = new Array("a", "all", "am", "an", "and", "any", "are", "as", "at", "be", "but", "by", "can", "can't", "did", "didn't", "do", "does", "doesn't", "don't", "else", "for", "get", "gets", "go", "got", "had", "has", "he", "he's", "her", "here", "hers", "hi", "him", "his", "how", "i'd", "i'll", "i'm", "i've", "if", "in", "is", "isn't", "it", "it's", "its", "let", "let's", "may", "me", "my", "no", "of", "off", "on", "our", "ours", "she", "so", "than", "that", "that's", "thats", "the", "their", "theirs", "them", "then", "there", "there's", "these", "they", "they'd", "they'll", "they're", "they've", "this", "those", "to", "too", "try", "until", "us", "want", "wants", "was", "wasn't", "we", "we'd", "we'll", "we're", "we've", "well", "went", "were", "weren't", "what", "what's", "when", "where", "which", "who", "who's", "whose", "why", "will", "with", "won't", "would", "yes", "yet", "you", "you'd", "you'll", "you're", "you've", "your");

// Only significant words are transformed. Handles acronyms and punctuation
String.prototype.toTitleCase = function() {
    var newSentence = true;
    return this.split(/\s+/).map(function(word) {
        if (word == "") { return; }
        var canCapitalise = true;
        // Get the pos of the first alpha char (word might start with " or ')
        var firstAlphaCharPos = word.search(/\w/);
        // Check for uppercase char that is not the first char (might be acronym or all caps)
        if (word.search(/[A-Z]/) > 0) {
            canCapitalise = false;
        } else if (stopWordsArray.indexOf(word) != -1) {
            // Is a stop word and not a new sentence
            word.toLowerCase();
            if (!newSentence) {
                canCapitalise = false;
            }
        }
        // Is this the last word in a sentence?
        newSentence = (word.search(/[\.!\?:]['"]?$/) > 0)? true : false;
        return (canCapitalise)? word.replace(word[firstAlphaCharPos], word[firstAlphaCharPos].toUpperCase()) : word;
    }).join(' ');
}

// Pass a string using dot notation:
alert("A critical examination of Plato's view of the human nature".toTitleCase());
var str = "Ten years on: a study into the effectiveness of NCEA in New Zealand schools";
str.toTitleCase());
str = "\"Where to from here?\" the effectivness of eLearning in childhood education";
alert(str.toTitleCase());

/* Result:
A Critical Examination of Plato's View of the Human Nature.
Ten Years On: A Study Into the Effectiveness of NCEA in New Zealand Schools.
"Where to From Here?" The Effectivness of eLearning in Childhood Education. */

使用/\S+/g支持变音符:

function toTitleCase(str) replace str.replace(/\S+/g, str => str.charAt(0). toupbelise (str.substr, 1); 的 控制台(toTitleCase(“一个城市叫orebro”);-一个叫Orebro的城市

然而:“阳光(黄色)”⇒“阳光(黄色)”

瓦尔·弦=“测试” 笨蛋。 var输出=弦。charAt(0) 控制台日志(输出)。 警报(输出)

  
 var string = "tEsT"

 string = string.toLowerCase() 

 string.charAt(0).toUpperCase() + string.slice(1)

string.charAt(0) returns the character at the 0th index of the string. toUpperCase() is a method that returns the uppercase equivalent of a string. It is applied to the first character of the string, returned by charAt(0). string.slice(1) returns a new string that starts from the 1st index (the character at index 0 is excluded) till the end of the string. Finally, the expression concatenates the result of toUpperCase() and string.slice(1) to create a new string with the first character capitalized.