JavaScript实现密码输入框实时验证功能

<!DOCTYPE html>
<html lang="en">
 
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div {
            width: 600px;
            margin: 100px auto;
        }
        
        .message {
            display: inline-block;
            font-size: 12px;
            color: #999;
            background: url(./img/1.png) no-repeat left center;
            padding-left: 10px;
        }
        
        .wrong {
            color: red;
            background-image: url(img/2.png);
        }
        
        .right {
            color: green;
            background-image: url(img/3.png);
        }
    </style>
</head>
 
<body>
    <div class="register">
        <input type="password" class="ipt">
        <p class="message">请输入6-16位密码</p>
    </div>
    <script>
        //获取元素
        var ipt = document.querySelector('.ipt');
        var message = document.querySelector('.message');
        //注册事件
        ipt.onblur = function() {
            //根据表单的值的长度
            if (this.value.length < 6 || this.value.length > 16) {
                message.className = 'message wrong';
                message.innerHTML = '你输入的位数不对';
            } else {
                message.className = 'message right';
                message.innerHTML = '输入正确';
            }
        }
    </script>
</body>
 
</html>