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
jQuery:
$('some_element').keypress(function(e){
if(e.keyCode == 20){
//caps lock was pressed
}
});
这个jQuery插件(代码)实现了与Rajesh的回答相同的想法，更简洁一点。
其他回答
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>
Many existing answers will check for caps lock on when shift is not pressed but will not check for it if you press shift and get lowercase, or will check for that but will not also check for caps lock being off, or will check for that but will consider non-alpha keys as 'off'. Here is an adapted jQuery solution that will show a warning if an alpha key is pressed with caps (shift or no shift), will turn off the warning if an alpha key is pressed without caps, but will not turn the warning off or on when numbers or other keys are pressed.
$("#password").keypress(function(e) {
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)) {
$("#CapsWarn").show();
} else if ((s.toLowerCase() === s && s.toUpperCase() !== s && !e.shiftKey)||
(s.toLowerCase() !== s && s.toUpperCase() === s && e.shiftKey)) { //caps is off
$("#CapsWarn").hide();
} //else upper and lower are both same (i.e. not alpha key - so do not hide message if already on but do not turn on if alpha keys not hit yet)
});
这是一个自定义的jquery插件，使用jquery ui，由这个页面上的所有好主意和工具提示小部件组成。大写锁定消息是自动应用于所有密码框，不需要更改您当前的html。
自定义插件代码…
(function ($) {
$.fn.capsLockAlert = function () {
return this.each(function () {
var capsLockOn = false;
var t = $(this);
var updateStatus = function () {
if (capsLockOn) {
t.tooltip('open');
} else {
t.tooltip('close');
}
}
t.tooltip({
items: "input",
position: { my: "left top", at: "left bottom+10" },
open: function (event, ui) {
ui.tooltip.css({ "min-width": "100px", "white-space": "nowrap" }).addClass('ui-state-error');
if (!capsLockOn) t.tooltip('close');
},
content: function () {
return $('<p style="white-space: nowrap;"/>')
.append($('<span class="ui-icon ui-icon-alert" style="display: inline-block; margin-right: 5px; vertical-align: text-top;" />'))
.append('Caps Lock On');
}
})
.off("mouseover mouseout")
.keydown(function (e) {
if (e.keyCode !== 20) return;
capsLockOn = !capsLockOn;
updateStatus();
})
.keypress(function (e) {
var kc = e.which; //get keycode
var isUp = (kc >= 65 && kc <= 90) ? true : false; // uppercase
var isLow = (kc >= 97 && kc <= 122) ? true : false; // lowercase
if (!isUp && !isLow) return; //This isn't a character effected by caps lock
// event.shiftKey does not seem to be normalized by jQuery(?) for IE8-
var isShift = (e.shiftKey) ? e.shiftKey : ((kc === 16) ? true : false); // shift is pressed
// uppercase w/out shift or lowercase with shift == caps lock
if ((isUp && !isShift) || (isLow && isShift)) {
capsLockOn = true;
} else {
capsLockOn = false;
}
updateStatus();
});
});
};
})(jQuery);
适用于所有密码元素…
$(function () {
$(":password").capsLockAlert();
});
显示大写锁定状态的变量:
let isCapsLockOn = false;
document.addEventListener( 'keydown', function( event ) {
var caps = event.getModifierState && event.getModifierState( 'CapsLock' );
if(isCapsLockOn !== caps) isCapsLockOn = caps;
});
document.addEventListener( 'keyup', function( event ) {
var caps = event.getModifierState && event.getModifierState( 'CapsLock' );
if(isCapsLockOn !== caps) isCapsLockOn = caps;
});
适用于所有浏览器=> canIUse
@user110902发布的这个基于jquery的回答对我很有用。然而，我对它进行了一些改进，以防止@B_N的评论中提到的缺陷:当你按Shift时，它无法检测到CapsLock:
$('#example').keypress(function(e) {
var s = String.fromCharCode( e.which );
if (( s.toUpperCase() === s && s.toLowerCase() !== s && !e.shiftKey )
|| ( s.toLowerCase() === s && s.toUpperCase() !== s && e.shiftKey )) {
alert('caps is on');
}
});
像这样，即使按下Shift，它也会工作。
