SOURCE

function writeDocument(variable) {
    document.write(variable + "<br/>");
} 

writeDocument("---定义时间对象---------------");
var oToday = new Date();

writeDocument("---获取年、月、日、时、分、秒、毫秒---------------");
writeDocument("年："+oToday.getFullYear());
writeDocument("月："+oToday.getMonth());
writeDocument("日："+oToday.getDate());
writeDocument("时："+oToday.getHours());
writeDocument("分："+oToday.getMinutes());
writeDocument("秒："+oToday.getSeconds());
writeDocument("毫秒："+oToday.getMilliseconds());

writeDocument("---设置年、月、日、时、分、秒、毫秒---------------");
var oDate = new Date(2019);

oDate.setFullYear(2020);
writeDocument("年："+oToday.getFullYear());
oDate.setMonth(5);
writeDocument("月："+oToday.getMonth());
oDate.setDate(1);
writeDocument("日："+oToday.getDate());

oDate.setHours(16);
writeDocument("时："+oToday.getHours());
oDate.setMinutes(58);
writeDocument("分："+oToday.getMinutes());
oDate.setSeconds(59);
writeDocument("秒："+oToday.getSeconds());
oDate.setMilliseconds(105);
writeDocument("毫秒："+oToday.getMilliseconds());

var weeks = [,"星期一","星期二","星期三","星期四","星期五","星期六"];
writeDocument("今天是"+weeks[oToday.getDay()]);
var oPrintDate = new Date(2019,5,1,15,59,59,99);

writeDocument("---打印2019年6月1日 星期六 15：59：59：99-------------"); 
writeDocument(oPrintDate.getFullYear()+"年"
             +oPrintDate.getMonth()+"月"
             +oPrintDate.getDate()+"日"
             +" "
             +weeks[oPrintDate.getDay()]
             +" "
             +oPrintDate.getHours()+":"
             +oPrintDate.getMinutes()+":"
             +oPrintDate.getSeconds()+":"
             +oPrintDate.getMilliseconds());