javascript获取当前日期和时间

function GetDate(format) {
/**
     * format=1表示获取年月日
     * format=0表示获取年月日时分秒
     * **/
     var now = new Date();
     var year = now.getFullYear();
     var month = now.getMonth()+1;
     var date = now.getDate();
     var day = now.getDay();//得到周几
     var hour = now.getHours();//得到小时
     var minu = now.getMinutes();//得到分钟
     var sec = now.getSeconds();//得到秒
     if (format==1){
_time = year+"-"+month+"-"+date
    }
else if (format==2){
_time = year+"-"+month+"-"+date+" "+hour+":"+minu+":"+sec
    }
return _time
}    

alert("当前日期为: " + GetDate(0));