输入密码检测大写是否锁定js实现代码

<div>
<input class="text" name="passwd" id="loginPasswd" type="password" style="*display:block;" />
<div style="color:#F90;padding:2px; position:absolute; display:none;" id="capital">大写锁定已开启</div>
<script type="text/javascript"><!--
(function(){
var inputPWD = document.getElementById('loginPasswd');
var capital = false;
var capitalTip = {
elem:document.getElementById('capital'),
toggle:function(s){
var sy = this.elem.style;
var d = sy.display;
if(s){
sy.display = s;
}else{
sy.display = d =='none' ? '' : 'none';
}
}
}
var detectCapsLock = function(event){
if(capital){return};
var e = event||window.event;
var keyCode = e.keyCode||e.which; // 按键的keyCode
var isShift = e.shiftKey ||(keyCode == 16 ) || false ; // shift键是否按住
if (
((keyCode >= 65 && keyCode <= 90 ) && !isShift) // Caps Lock 打开，且没有按住shift键
|| ((keyCode >= 97 && keyCode <= 122 ) && isShift)// Caps Lock 打开，且按住shift键
){capitalTip.toggle('block');capital=true}
else{capitalTip.toggle('none');}
}
inputPWD.onkeypress = detectCapsLock;
inputPWD.onkeyup=function(event){
var e = event||window.event;
if(e.keyCode == 20 && capital){
capitalTip.toggle();
return false;
}
}
})()
// --></script>
</div>