JavaScript实现密码框实时验证功能

<!DOCTYPE html>
<html>
 <head>
  <meta charset="utf-8">
  <title></title>
  <link rel="stylesheet" type="text/css" href="fontss2/iconfont.css" rel="external nofollow" />
  <style>
   .orginal {
    font-size: 13px;
    color: deepskyblue;
   }
   .wrong {
    font-size: 13px;
    color: red;  
   }
   .right {
    font-size: 13px;
    color: green;
   }
  </style>
 </head>
 <body>
  <p>
   <input type="text"><span class="orginal icon-wenhao iconfont">请输入6-16位密码</span>
  </p>
  <script>
   //获取元素对象
   var input = document.querySelector('input');
   var span = document.querySelector('span');

   // 注册事件 失去焦点事件
   input.onblur = function() {
    if (input.value.length > 0 && input.value.length < 6 || input.value.length > 16) {
     span.className = 'iconfont icon-cuowuguanbiquxiao-xianxingyuankuang wrong';
     span.innerHTML= '输入错误请输入6-16位密码';
    }else if(input.value.length >=6 && input.value.length <=16) {
     span.className = 'iconfont  icon-yiyanzheng  right';
     span.innerHTML = '输入正确';
    }else {
     span.className = 'orginal icon-wenhao iconfont';
     span.innerHTML = '请输入6-16位密码';
    }
   }
  </script>
 </body>
</html>