你如何告诉如果大写锁定使用JavaScript?
但有一个警告:我做了谷歌，我能找到的最好的解决方案是附加一个onkeypress事件到每个输入，然后检查每次按下的字母是否大写，如果是，然后检查shift是否也按下。如果不是，那么caps lock必须是打开的。这感觉真的很脏，而且…浪费——肯定有比这更好的办法吗?
当前回答
基于@joshuahedlund的回答，因为它对我来说很好。
我把代码变成了一个函数，这样就可以重用它，并在我的例子中把它链接到正文。如果您愿意，可以将其链接到密码字段。
<html>
<head>
<script language="javascript" type="text/javascript" >
function checkCapsLock(e, divId) {
if(e){
e = e;
} else {
e = window.event;
}
var s = String.fromCharCode( e.which );
if ((s.toUpperCase() === s && s.toLowerCase() !== s && !e.shiftKey)|| //caps is on
(s.toUpperCase() !== s && s.toLowerCase() === s && e.shiftKey)) {
$(divId).style.display='block';
} else if ((s.toLowerCase() === s && s.toUpperCase() !== s && !e.shiftKey)||
(s.toLowerCase() !== s && s.toUpperCase() === s && e.shiftKey)) { //caps is off
$(divId).style.display='none';
} //else upper and lower are both same (i.e. not alpha key - so do not hide message if already on but do not turn on if alpha keys not hit yet)
}
</script>
<style>
.errorDiv {
display: none;
font-size: 12px;
color: red;
word-wrap: break-word;
text-overflow: clip;
max-width: 200px;
font-weight: normal;
}
</style>
</head>
<body onkeypress="checkCapsLock(event, 'CapsWarn');" >
...
<input name="password" id="password" type="password" autocomplete="off">
<div id="CapsWarn" class="errorDiv">Capslock is ON !</div>
...
</body>
</html>
其他回答
如何使用getModifierState()
如果指定了修饰符，getModifierState()方法返回true 按键被按下或激活。
你可以这样使用它:
function checkIfCapsLockIsOn(event) {
var capsLockIsOn = event.getModifierState("CapsLock");
console.log("Caps Lock activated: " + capsLockIsOn);
}
这将简单地检查CapsLock是ON还是OFF，并在控制台显示它。你可以改变函数的工作方式。
然后在keydown或keyup上使用这个函数。
<input type="text" onkeydown="checkIfCapsLockIsOn(event)">
您可以使用KeyboardEvent来检测许多按键，包括最新浏览器上的大写锁。
getModifierState函数将提供以下状态:
Alt AltGraph 大写锁定 控制 Fn (Android) 元 时键盘上的数字 操作系统(Windows & Linux) ScrollLock 转变
这个演示工作在所有主要的浏览器，包括移动(caniuse)。
passwordField.addEventListener( 'keydown', function( event ) {
var caps = event.getModifierState && event.getModifierState( 'CapsLock' );
console.log( caps ); // true when you press the keyboard CapsLock key
});
We use getModifierState to check for caps lock, it's only a member of a mouse or keyboard event so we cannot use an onfocus. The most common two ways that the password field will gain focus is with a click in or a tab. We use onclick to check for a mouse click within the input, and we use onkeyup to detect a tab from the previous input field. If the password field is the only field on the page and is auto-focused then the event will not happen until the first key is released, which is ok but not ideal, you really want caps lock tool tips to display once the password field gains focus, but for most cases this solution works like a charm.
HTML
<input type="password" id="password" onclick="checkCapsLock(event)" onkeyup="checkCapsLock(event)" />
JS
function checkCapsLock(e) {
if (e.getModifierState("CapsLock")) {
console.log("Caps");
}
}
https://codepen.io/anon/pen/KxJwjq
这是一种解决方案，除了在写入时检查状态外，还在每次按下Caps Lock键时切换警告消息(有一些限制)。
它还支持A-Z范围之外的非英语字母，因为它根据toUpperCase()和toLowerCase()检查字符串字符，而不是根据字符范围检查。
$(function(){ //Initialize to hide caps-lock-warning $('.caps-lock-warning').hide(); //Sniff for Caps-Lock state $("#password").keypress(function(e) { var s = String.fromCharCode( e.which ); if((s.toUpperCase() === s && s.toLowerCase() !== s && !e.shiftKey)|| (s.toUpperCase() !== s && s.toLowerCase() === s && e.shiftKey)) { this.caps = true; // Enables to do something on Caps-Lock keypress $(this).next('.caps-lock-warning').show(); } else if((s.toLowerCase() === s && s.toUpperCase() !== s && !e.shiftKey)|| (s.toLowerCase() !== s && s.toUpperCase() === s && e.shiftKey)) { this.caps = false; // Enables to do something on Caps-Lock keypress $(this).next('.caps-lock-warning').hide(); }//else else do nothing if not a letter we can use to differentiate }); //Toggle warning message on Caps-Lock toggle (with some limitation) $(document).keydown(function(e){ if(e.which==20){ // Caps-Lock keypress var pass = document.getElementById("password"); if(typeof(pass.caps) === 'boolean'){ //State has been set to a known value by keypress pass.caps = !pass.caps; $(pass).next('.caps-lock-warning').toggle(pass.caps); } } }); //Disable on window lost focus (because we loose track of state) $(window).blur(function(e){ // If window is inactive, we have no control on the caps lock toggling // so better to re-set state var pass = document.getElementById("password"); if(typeof(pass.caps) === 'boolean'){ pass.caps = null; $(pass).next('.caps-lock-warning').hide(); } }); }); <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <input type="password" id="password" /> <span class="caps-lock-warning" title="Caps lock is on!">CAPS</span>
注意，只有在按下caps lock键之前知道caps lock的状态时，观察caps lock切换才有用。当前的大写锁定状态由密码元素上的caps JavaScript属性保持。这是当用户按下一个大写或小写字母时，我们第一次验证大写锁定状态时设置的。如果窗口失去焦点，我们就不能再观察到caps锁定切换，所以我们需要重置到未知状态。
Javascript代码
<script type="text/javascript">
function isCapLockOn(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('alert').style.visibility = 'visible';
else
document.getElementById('alert').style.visibility = 'hidden';
}
</script>
现在我们需要使用Html来关联这个脚本
<input type="password" name="txtPassword" onkeypress="isCapLockOn(event)" />
<div id="alert" style="visibility:hidden">Caps Lock is on.</div>
