text-transform: capitalize;

CSS已经得到了它:)

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(" ");
}

function titleCase(str) {

    var myString = str.toLowerCase().split(' ');
    for (var i = 0; i < myString.length; i++) {
        var subString = myString[i].split('');
        for (var j = 0; j < subString.length; j++) {
            subString[0] = subString[0].toUpperCase();
        }
        myString[i] = subString.join('');
    }

    return myString.join(' ');
}

我已经使用下面的代码做到了这一点，希望它能帮助你:

<p id="p1">This is a paragraph.</p>

<script>
   const capitalize = (mySentence) => {
      const words = mySentence.split(" ");
      for (let i = 0; i < words.length; i++) {
         words[i] = words[i][0].toUpperCase() + words[i].substr(1);
      }
      return words.join(" ");
   };  
   const result = capitalize('This is a sample text');
   document.getElementById("p1").innerHTML = result;
</script>

下面的函数不改变字符串的任何其他部分，只是试图将所有单词的所有首字母(即通过正则表达式定义\w+)转换为大写。

这意味着它不一定会将单词转换为标题，而是完全按照问题的标题说的那样:“字符串中每个单词的首字母大写- JavaScript”

不要扯断绳子 通过等价于[A-Za-z0-9_]+的正则表达式\w+确定每个单词 只对每个单词的第一个字符应用String.prototype.toUpperCase()函数。

function first_char_to_uppercase(argument) {
  return argument.replace(/\w+/g, function(word) {
    return word.charAt(0).toUpperCase() + word.slice(1);
  });
}

例子:

first_char_to_uppercase("I'm a little tea pot");
// "I'M A Little Tea Pot"
// This may look wrong to you, but was the intended result for me
// You may wanna extend the regex to get the result you desire, e.g., /[\w']+/

first_char_to_uppercase("maRy hAd a lIttLe LaMb");
// "MaRy HAd A LIttLe LaMb"
// Again, it does not convert words to Titlecase

first_char_to_uppercase(
  "ExampleX: CamelCase/UPPERCASE&lowercase,exampleY:N0=apples"
);
// "ExampleX: CamelCase/UPPERCASE&Lowercase,ExampleY:N0=Apples"

first_char_to_uppercase("…n1=orangesFromSPAIN&&n2!='a sub-string inside'");
// "…N1=OrangesFromSPAIN&&N2!='A Sub-String Inside'"

first_char_to_uppercase("snake_case_example_.Train-case-example…");
// "Snake_case_example_.Train-Case-Example…"
// Note that underscore _ is part of the RegEx \w+

first_char_to_uppercase(
  "Capitalize First Letter of each word in a String - JavaScript"
);
// "Capitalize First Letter Of Each Word In A String - JavaScript"

编辑2019-02-07:如果你想要真正的标题(即只有第一个字母大写，其他字母小写):

function titlecase_all_words(argument) {
  return argument.replace(/\w+/g, function(word) {
    return word.charAt(0).toUpperCase() + word.slice(1).toLowerCase();
  });
}

显示两者的例子:

test_phrases = [
  "I'm a little tea pot",
  "maRy hAd a lIttLe LaMb",
  "ExampleX: CamelCase/UPPERCASE&lowercase,exampleY:N0=apples",
  "…n1=orangesFromSPAIN&&n2!='a sub-string inside'",
  "snake_case_example_.Train-case-example…",
  "Capitalize First Letter of each word in a String - JavaScript"
];
for (el in test_phrases) {
  let phrase = test_phrases[el];
  console.log(
    phrase,
    "<- input phrase\n",
    first_char_to_uppercase(phrase),
    "<- first_char_to_uppercase\n",
    titlecase_all_words(phrase),
    "<- titlecase_all_words\n "
  );
}

// I'm a little tea pot <- input phrase
// I'M A Little Tea Pot <- first_char_to_uppercase
// I'M A Little Tea Pot <- titlecase_all_words

// maRy hAd a lIttLe LaMb <- input phrase
// MaRy HAd A LIttLe LaMb <- first_char_to_uppercase
// Mary Had A Little Lamb <- titlecase_all_words

// ExampleX: CamelCase/UPPERCASE&lowercase,exampleY:N0=apples <- input phrase
// ExampleX: CamelCase/UPPERCASE&Lowercase,ExampleY:N0=Apples <- first_char_to_uppercase
// Examplex: Camelcase/Uppercase&Lowercase,Exampley:N0=Apples <- titlecase_all_words

// …n1=orangesFromSPAIN&&n2!='a sub-string inside' <- input phrase
// …N1=OrangesFromSPAIN&&N2!='A Sub-String Inside' <- first_char_to_uppercase
// …N1=Orangesfromspain&&N2!='A Sub-String Inside' <- titlecase_all_words

// snake_case_example_.Train-case-example… <- input phrase
// Snake_case_example_.Train-Case-Example… <- first_char_to_uppercase
// Snake_case_example_.Train-Case-Example… <- titlecase_all_words

// Capitalize First Letter of each word in a String - JavaScript <- input phrase
// Capitalize First Letter Of Each Word In A String - JavaScript <- first_char_to_uppercase
// Capitalize First Letter Of Each Word In A String - Javascript <- titlecase_all_words

ECMAScript 6版本:

const toTitleCase =(短语)=> { 返回的短语 .toLowerCase () .split (' ') .map(word => word. charat (0).toUpperCase() + word.slice(1)) . join (' '); }; let result = toTitleCase('maRy have a lIttLe LaMb'); console.log(结果);