var t = null;
t = setTimeout(time, 1000);//開始运行
function time() {
    clearTimeout(t);//清除定时器
    dt = new Date();
    var y = dt.getFullYear();
    var mt = dt.getMonth() + 1;
    var day = dt.getDate();
    var h = dt.getHours();//获取时
    var m = dt.getMinutes();//获取分
    var s = dt.getSeconds();//获取秒
    var t = null;
    document.getElementById("showTime").innerHTML = y + "/" + Appendzero(mt) + "/" + Appendzero(day) + " " + Appendzero(h) + ":" + Appendzero(m) + ":" + Appendzero(s) + "";

    function Appendzero(obj) {
        if (obj < 10) return "0" + "" + obj;
        else return obj;
    }

    t = setTimeout(time, 1000); //设定定时器，循环运行
}