js获取当前时间(昨天、今天、明天)

//昨天的时间
var day1 = new Date();
day1.setTime(day1.getTime()-24*60*60*1000);
var s1 = day1.getFullYear()+"-" + (day1.getMonth()+1) + "-" + day1.getDate();
//今天的时间
var day2 = new Date();
day2.setTime(day2.getTime());
var s2 = day2.getFullYear()+"-" + (day2.getMonth()+1) + "-" + day2.getDate();
//明天的时间
var day3 = new Date();
day3.setTime(day3.getTime()+24*60*60*1000);
var s3 = day3.getFullYear()+"-" + (day3.getMonth()+1) + "-" + day3.getDate();
//拼接时间
function show(){
  var str = "" + s1 + "至" + s2;
  return str;
}
//赋值doubleDate
 $('#dateS').val(show());

function writeCurrentDate() {
    var now = new Date();
    var year = now.getFullYear(); //得到年份
    var month = now.getMonth();//得到月份
    var date = now.getDate();//得到日期
    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
　　   var MS = now.getMilliseconds();//获取毫秒
    var week;
    month = month + 1;
    if (month < 10) month = "0" + month;
    if (date < 10) date = "0" + date;
    if (hour < 10) hour = "0" + hour;
    if (minu < 10) minu = "0" + minu;
    if (sec < 10) sec = "0" + sec;
    if （MS < 100）MS = "0" + MS;
    var arr_week = new Array("星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六");
    week = arr_week[day];
    var time = "";
    time = year + "年" + month + "月" + date + "日" + " " + hour + ":" + minu + ":" + sec + " " + week;
    //当前日期赋值给当前日期输入框中（jQuery easyUI）
    $("#currentDate").html(time);
    //设置得到当前日期的函数的执行间隔时间，每1000毫秒刷新一次。
    var timer = setTimeout("writeCurrentDate()", 1000);
   }