原生js下拉刷新

<!DOCTYPE html>
<html>

   <head>
       <meta charset="UTF-8">
       <title></title>
       <meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" />
       <style type="text/css">
           body {
               font-size: 12px;
               -webkit-user-select: none;
               -webkit-text-size-adjust: none;
               font-family: helvetica;
           }

           #slideDown {
               margin-top: 0;
               width: 100%;
           }

           #slideDown1,
           #slideDown2 {
               width: 100%;
               background: #e9f4f7;
               display: none;
           }

           #slideDown1 {
               height: 20px;
           }

           #slideDown1>p,
           #slideDown2>p {
               margin: 20px auto;
               text-align: center;
               font-size: 14px;
               color: #37bbf5;
           }

           #content {
               position: absolute;
               left: 0;
               top: 0;
               z-index: 1;
               /*   -webkit-touch-callout:none;*/
               -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
               width: 100%;
               padding: 0;
           }
       </style>
   </head>

   <body>
       <div + _end);
                       slideDownStep2();
                       //刷新成功则
                       //模拟刷新成功进入第三步
                       setTimeout(function() {
                           slideDownStep3();
                       }, 2500);
                   }
               }
           }
       </script>
   </body>

</html>