js取得当前时间

window.onload = function getNowTime(){
    //取得当前时间
    var now= new Date();
    var year=now.getYear();
    var month=now.getMonth()+1;
    var day=now.getDate();
    var hour=now.getHours();
    var minute=now.getMinutes();
    var second=now.getSeconds();
    var myweekday=now.getDay();
    var weekday="";
        if(myweekday == 0)
        weekday=" 星期日";
        else if(myweekday == 1)
        weekday=" 星期一";
        else if(myweekday == 2)
        weekday=" 星期二";
        else if(myweekday == 3)
        weekday=" 星期三";
        else if(myweekday == 4)
        weekday=" 星期四";
        else if(myweekday == 5)
        weekday=" 星期五";
        else if(myweekday == 6)
        weekday=" 星期六";

    var nowdate=year+"年"+month+"月"+day+"日 "+ weekday+" " +hour+":"+minute+":"+second;
    document.getElementById("mydate_").innerText = nowdate;
}