每隔一段时间运作javascript

每隔一段时间运行javascript
    <script language="javascript" type="text/javascript">
       function online() {
           $.ajax({
               type: "post",
               url: "HeardManage.aspx",
               data: "1010",
               success: function() {
                 
               }
           });
       }
      
      setInterval(online,3000);
    
    </script>