还有另一个版本，清晰而简单，处理移位的capsLock，并且不受ascii限制，我认为:

document.onkeypress = function (e)
{
    e = e || window.event;
    if (e.charCode === 0 || e.ctrlKey || document.onkeypress.punctuation.indexOf(e.charCode) >= 0)
        return;
    var s = String.fromCharCode(e.charCode); // or e.keyCode for compatibility, but then have to handle MORE non-character keys
    var s2 = e.shiftKey ? s.toUpperCase() : s.toLowerCase();
    var capsLockOn = (s2 !== s);
    document.getElementById('capslockWarning').style.display = capsLockOn ? '' : 'none';
}
document.onkeypress.punctuation = [33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,91,92,93,94,95,96,123,124,125,126];

编辑:意义上的capsLockOn被逆转，多，固定。

编辑#2:在进一步检查之后，我做了一些更改，不幸的是，代码更详细了一些，但它可以适当地处理更多的操作。

Using e.charCode instead of e.keyCode and checking for 0 values skips a lot of non-character keypresses, without coding anything specific to a given language or charset. From my understanding, it's slightly less compatible, so older, non-mainstream, or mobile browsers may not behave as this code expects, but it's worth it, for my situation anyway. Checking against a list of known punctuation codes prevents them from being seen as false negatives, since they're not affected by caps lock. Without this, the caps lock indicator gets hidden when you type any of those punctuation characters. By specifying an excluded set, rather than an included one, it should be more compatible with extended characters. This is the ugliest, special-casiest bit, and there's some chance that non-Western languages have different enough punctuation and/or punctuation codes to be a problem, but again it's worth it IMO, at least for my situation.

所以我找到了这个页面，并不是很喜欢我找到的解决方案，所以我想出了一个，并把它提供给你们所有人。对我来说，只有当我输入字母时，大写锁才重要。这段代码为我解决了问题。它快速和简单，给你一个辣椒变量引用，只要你需要它。

let capsIsOn=false; let capsChecked=false; let capsCheck=(e)=>{ let letter=e.key; if(letter.length===1 && letter.match(/[A-Za-z]/)){ if(letter!==letter.toLowerCase()){ capsIsOn=true; console.log('caps is on'); }else{ console.log('caps is off'); } capsChecked=true; window.removeEventListener("keyup",capsCheck); }else{ console.log("not a letter, not capsCheck was performed"); } } window.addEventListener("keyup",capsCheck); window.addEventListener("keyup",(e)=>{ if(capsChecked && e.keyCode===20){ capsIsOn=!capsIsOn; } });

试试这个简单的代码，容易理解

这是脚本

 <script language="Javascript">
function capLock(e){
 kc = e.keyCode?e.keyCode:e.which;
 sk = e.shiftKey?e.shiftKey:((kc == 16)?true:false);
 if(((kc >= 65 && kc <= 90) && !sk)||((kc >= 97 && kc <= 122) && sk))
  document.getElementById('divMayus').style.visibility = 'visible';
 else
   document.getElementById('divMayus').style.visibility = 'hidden';
}
</script>

还有Html

<input type="password" name="txtPassword" onkeypress="capLock(event)" />
 <div id="divMayus" style="visibility:hidden">Caps Lock is on.</div> 

还有另一个版本，清晰而简单，处理移位的capsLock，并且不受ascii限制，我认为:

document.onkeypress = function (e)
{
    e = e || window.event;
    if (e.charCode === 0 || e.ctrlKey || document.onkeypress.punctuation.indexOf(e.charCode) >= 0)
        return;
    var s = String.fromCharCode(e.charCode); // or e.keyCode for compatibility, but then have to handle MORE non-character keys
    var s2 = e.shiftKey ? s.toUpperCase() : s.toLowerCase();
    var capsLockOn = (s2 !== s);
    document.getElementById('capslockWarning').style.display = capsLockOn ? '' : 'none';
}
document.onkeypress.punctuation = [33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,91,92,93,94,95,96,123,124,125,126];

编辑:意义上的capsLockOn被逆转，多，固定。

编辑#2:在进一步检查之后，我做了一些更改，不幸的是，代码更详细了一些，但它可以适当地处理更多的操作。

Using e.charCode instead of e.keyCode and checking for 0 values skips a lot of non-character keypresses, without coding anything specific to a given language or charset. From my understanding, it's slightly less compatible, so older, non-mainstream, or mobile browsers may not behave as this code expects, but it's worth it, for my situation anyway. Checking against a list of known punctuation codes prevents them from being seen as false negatives, since they're not affected by caps lock. Without this, the caps lock indicator gets hidden when you type any of those punctuation characters. By specifying an excluded set, rather than an included one, it should be more compatible with extended characters. This is the ugliest, special-casiest bit, and there's some chance that non-Western languages have different enough punctuation and/or punctuation codes to be a problem, but again it's worth it IMO, at least for my situation.

你可以试试。增加了一个工作示例。当焦点在输入上时，打开caps lock使led变成红色或绿色。(还没有在mac/linux上测试)

注意:两个版本都适用于我。感谢您在评论中提出建设性意见。

旧版本:https://jsbin.com/mahenes/edit?js,output

另外，这是一个修改后的版本(有人能在mac上测试并确认吗)

新版本:https://jsbin.com/xiconuv/edit?js,output

新版本:

function isCapslock(e) {
  const IS_MAC = /Mac/.test(navigator.platform);

  const charCode = e.charCode;
  const shiftKey = e.shiftKey;

  if (charCode >= 97 && charCode <= 122) {
    capsLock = shiftKey;
  } else if (charCode >= 65 && charCode <= 90
    && !(shiftKey && IS_MAC)) {
    capsLock = !shiftKey;
  }

  return capsLock;
}

旧版本:

function isCapslock(e) {
  e = (e) ? e : window.event;

  var charCode = false;
  if (e.which) {
    charCode = e.which;
  } else if (e.keyCode) {
    charCode = e.keyCode;
  }

  var shifton = false;
  if (e.shiftKey) {
    shifton = e.shiftKey;
  } else if (e.modifiers) {
    shifton = !!(e.modifiers & 4);
  }

  if (charCode >= 97 && charCode <= 122 && shifton) {
    return true;
  }

  if (charCode >= 65 && charCode <= 90 && !shifton) {
    return true;
  }

  return false;
}

对于国际字符，可以根据需要为以下键添加额外的检查。你必须获得你感兴趣的字符的键码范围，可能是通过使用一个键映射数组，它将保存你正在寻址的所有有效用例键…

大写字母A-Z或'Ä'， 'Ö'， 'Ü'， 小写字母a-Z或0-9或'ä'， 'ö'， 'ü'

上面的键只是示例表示。

我写了一个名为capsLock的库，它完全是你想要它做的。

只要把它包括在你的网页上:

<script src="https://rawgit.com/aaditmshah/capsLock/master/capsLock.js"></script>

然后像这样使用它:

alert(capsLock.status);

capsLock.observe(function (status) {
    alert(status);
});

参见演示:http://jsfiddle.net/3EXMd/

按下“Caps Lock”键更新状态。它只使用Shift键来确定Caps Lock键的正确状态。最初状态为false。所以要小心。