<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>
        <span id="a">
    </body>
</html>
<script>
    function b(){
    var a=document.getElementById("a")
   var time=new Date()
   var year=time.getFullYear()
   var month=time.getMonth()+1
   var day=time.getDay()
   var hour=time.getHours()
   var min=time.getMinutes()<10?"0"+time.getMinutes():time.getMinutes()
   var sec=time.getSeconds()<10?"0"+time.getSeconds():time.getSeconds()
   
   var get_time=year+"/"+month+"/"+day+"&nbsp;&nbsp"+hour+":"+min+":"+sec
   a.innerHTML=get_time
  }
  window.setInterval("b()",500)
    
</script>