JavaScript实现密码框长度校验与提示功能

代码实现细节

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <meta http-equiv="X-UA-Compatible" content="ie=edge">
 <title>密码框</title>
 <style type="text/css">
 div{
  width: 600px;
  margin: 100px auto;
 }
  .massage{
   background-image: url(gth.png);
   background-repeat:no-repeat;
   background-position: left center;
   color:black;
   display: inline-block;
   padding-left: 20px;
  } 
  .right{
   background-image: url(right.png);
   background-repeat: no-repeat;
   color: green;
  }
  .wrong{
   background-repeat: no-repeat;
   background-image: url(wrong.png);
   color: red;
  }
 </style>
</head>
<body>
 <div class="register">
 <input type="password" id="pwd">
 <p class="massage">请输入6-16位密码</p>
 </div>
 <script>
  var pwd=document.querySelector('#pwd'); 
  var aa=document.querySelector('.massage');
  pwd.onblur= function(){
    if(this.value.length>16 || this.value.length<6){
     aa.innerText='错误，请输入6-16为密码';
     aa.className='massage wrong';
    }else{
    aa.className='massage right';
    aa.innerText='密码正确'; 
    }
  }
 </script>
</body>
</html>