js獲取當前日期的前一天、一月、一年的日期

function getYestoday(date){

    var yesterday_milliseconds=date.getTime()-10006060*24;

    var yesterday = new Date();

        yesterday.setTime(yesterday_milliseconds);


var strYear = yesterday.getFullYear();  
var strDay = yesterday.getDate();  
var strMonth = yesterday.getMonth()+1;
if(strMonth<10)  
{  
    strMonth="0"+strMonth;  
}  
datastr = strYear+"-"+strMonth+"-"+strDay;
return datastr;

}
//獲得上個月在昨天這一天的日期
  function getLastMonthYestdy(date){
     var daysInMonth = new Array([0],[31],[28],[31],[30],[31],[30],[31],[31],[30],[31],[30],[31]);
     var strYear = date.getFullYear();

     var strDay = date.getDate();

     var strMonth = date.getMonth()+1;
     if(strYear%4 == 0 && strYear%100 != 0){
        daysInMonth[2] = 29;
     }
     if(strMonth - 1 == 0)
     {
        strYear -= 1;
        strMonth = 12;
     }
     else
     {
        strMonth -= 1;
     }
     strDay = daysInMonth[strMonth] >= strDay ? strDay : daysInMonth[strMonth];
     if(strMonth<10)

     {

        strMonth="0"+strMonth;

     }
     if(strDay<10)

     {

        strDay="0"+strDay;

     }
     datastr = strYear+"-"+strMonth+"-"+strDay;
     return datastr;
  }
//獲得上一年在昨天這一天的日期
  function getLastYearYestdy(date){
     var strYear = date.getFullYear() - 1;

     var strDay = date.getDate();

     var strMonth = date.getMonth()+1;
     if(strMonth<10)

     {

        strMonth="0"+strMonth;

     }
     if(strDay<10)

     {

        strDay="0"+strDay;

     }
     datastr = strYear+"-"+strMonth+"-"+strDay;
     return datastr;
  }</pre>