js获取当前时间：

html 

<span id="show"></span>

js 

<script type="text/javascript">
window.onload = function() {
  var show = document.getElementById("show");
  setInterval(function() {
    var time = new Date();
    var m = time.getMonth() + 1;
    var t = time.getFullYear() + "-" + m + "-" +
      time.getDate() + " " + time.getHours() + ":" +
      time.getMinutes() + ":" + time.getSeconds();
    show.innerHTML = t;
  }, 1000);
};
</script>