js获取时间，时，分。秒

function GetDateStr1(AddDayCount) {   //年月日，时分秒

    /*document.write("前天："+GetDateStr(-2));
  document.write("<br />昨天："+GetDateStr(-1));
  document.write("<br />今天："+GetDateStr(0));
   document.write("<br />明天："+GetDateStr(1));
      document.write("<br />后天："+GetDateStr(2));
      document.write("<br />大后天："+GetDateStr(3));*/
        var dd = new Date();
 var seperator1 = "-";
    var seperator2 = ":";
    dd.setDate(dd.getDate()+AddDayCount);//获取AddDayCount天后的日期
    var y = dd.getFullYear();
    var m = dd.getMonth()+1;//获取当前月份的日期

  var d = dd.getDate();
    var h=dd.getHours();
    var mm=dd.getMinutes();
    var s=dd.getSeconds();
  m=m>9?m:"0"+m;      //格式化时间
    d=d>9?d:"0"+d;
    h=h>9?h:"0"+h;
    mm=mm>9?mm:"0"+mm;
    s=s>9?m:"0"+s;
  return y + seperator1 +m+ seperator1 + d   + " " + h + seperator2 + m+ seperator2 + s;

}

function date() {  //获取时间的js
    var date = new Date();
    var year = date.getFullYear();
    var month = date.getMonth() + 1;
    var day = date.getDate();//获取当前时间
    var afterday = parseInt(date.getDate())+1;//获取当前时间的后一天
   if (day < 10) {
        day = parseInt("0" + day);

    }
    var     nowDate = year + "-" + month + "-" + day;
    afterDate=year + "-" + month + "-" + afterday;
}
 
function GetDateStr2() {   //获取本月的第一天
    var dd = new Date();
    var y = dd.getFullYear();
    var m = dd.getMonth()+1;//获取当前月份的日期
    var d = "01";
    m=m>9?m:"0"+m;
    return y+"-"+m+"-"+d;
}
function GetDateStr3() {   //获取上月的第一天
    var nowdays = new Date();
    var year = nowdays.getFullYear();
    var month = nowdays.getMonth();
if(month==0)
    {
        month=12;
        year=year-1;
    }
    if (month < 10) {
        month = "0" + month;
    }

    return year + "-" + month + "-" + "01";//上个月的第一天
}
function GetDateStr4() {   //获取下月的第一天
    var nowdays = new Date();
    var year = nowdays.getFullYear();
    var month = nowdays.getMonth()+2;
  if(month==13)
    {
        month=1;
        year=year+1;
    }
    if (month < 10) {
        month = "0" + month;
    }

    return year + "-" + month + "-" + "01";//上个月的第一天
}