// Uppercase first letter
function ucfirst(field) {
    field.value = field.value.substr(0, 1).toUpperCase() + field.value.substr(1);
}

使用:

<input type="text" onKeyup="ucfirst(this)" />

function cap(input) {
    return input.replace(/[\.\r\n\t\:\;\?\!]\W*(\w)/g, function(match, capture) {
         // For other sentences in the text
         return match.toUpperCase();
    }).replace(/^\W*\w/, function(match, capture) {
        // For the first sentence in the text
        return match.toUpperCase();
    });;
}

var a = "hi, dear user. it is a simple test. see you later!\r\nbye";
console.log(cap(a));
// Output: Hi, dear user. It is a simple test. See you later!
// Bye

尝试下列功能:

function capitalize (string) {
  return [].map.call(string, (char, i) => i ? char : char.toUpperCase()).join('')
}

使用:

capitalize('hello, world!')

结果:

Hello, world!

将所有单词的第一字母分为一个字符串:

function ucFirstAllWords( str )
{
    var pieces = str.split(" ");
    for ( var i = 0; i < pieces.length; i++ )
    {
        var j = pieces[i].charAt(0).toUpperCase();
        pieces[i] = j + pieces[i].substr(1);
    }
    return pieces.join(" ");
}

function capitalize(s) {
    // returns the first letter capitalized + the string from index 1 and out aka. the rest of the string
    return s[0].toUpperCase() + s.substr(1);
}


// examples
capitalize('this is a test');
=> 'This is a test'

capitalize('the Eiffel Tower');
=> 'The Eiffel Tower'

capitalize('/index.html');
=> '/index.html'

如果您想修改全覆文本,您可能希望修改其他例子如下:

function capitalize (text) {
    return text.charAt(0).toUpperCase() + text.slice(1).toLowerCase();
}

这将确保下列文本进行更改:

TEST => Test
This Is A TeST => This is a test