<span id = "sj"></span>
window.setInterval (" time () , 500);
function time ()
{
var tm = new Date ();
var n = tm.getFullYear ();
var y = tm.getMonth ();
var r = tm.getDate ();
var h = tm.getHours ();
var m = tm.getMinutes ();
var s = tm.getSecounds ();
document.getElmentById("sj").innerText = n + "年" + y + "月" + r + "日 - -" + h + ":" + m + ":" + s;
}