DOM ------ 仿密码框提示语

//css代码
    div {
            width: 600px;
            margin: 100px auto;
        }
        .message {
            display: inline-block;
            font-size: 12px;
            color: #999;
        }
        .wrong {
            color: red;
        }
        .right{
            color: green;
        }
//html代码
        <div class="register">
          <input type="password" class="ipt">
          <p class="message">请输入6~16位密码</p>
      </div>
//js代码
        // 1.获取元素
        var ipt = document.querySelector('.ipt')
        var message = document.querySelector('.message')
        // 2.注册事件 失去焦点
        ipt.onblur = function() {
            if(this.value.length < 6|| this.value.length > 16){
                message.className = 'message wrong'
                message.innerHTML = '密码位数必须6~16位'
            }else{
                message.className = 'message right'
                message.innerHTML = '您输入的密码正确'
            }
        }