js实时获取并显示当前时间的方法

<script type="text/javascript">
 window.onload = function() {
  var show = document.getElementById("show");
  setInterval(function() {
   var time = new Date();
   // 程序计时的月从0开始取值后+1
   var m = time.getMonth() + 1;
   var t = time.getFullYear() + "-" + m + "-"
     + time.getDate() + " " + time.getHours() + ":"
     + time.getMinutes() + ":" + time.getSeconds();
   show.innerHTML = t;
  }, 1000);
 };
</script>