js倒计时，页面刷新时，不会从头计时

<div id=‘xx‘></div>
<script>
  var first_access_time = localStorage.getItem("first_access_time");
  var i = 10;
  if (first_access_time){
  　 var refresh_time = "<?php echo time();?>";
     time(i - (refresh_time - first_access_time));
  } else {
     localStorage.setItem("first_access_time", ‘<?php echo time();?>‘);
     time(i);
  }
  

  function time(i){
      if (i <=0){
        location.href = ‘http://www.google.cn‘;
        return;
      }
      document.getElementById(‘xx‘).innerHTML = i;
      setTimeout(‘time(‘+(--i)+‘)‘, 1000);
  }
</script>