jquery獲取前一個月日期

//將個數位日期轉為07
function p(s) {
    return s < 10 ? '0' + s: s;
}


//獲取一個月日期
function getcurrent() {
//將一個月的日期填入搜索框
    var currentYear=new Date().getFullYear();
    var currentMonth=new Date().getMonth()+1;  
    var currentDate=new Date().getDate();
    var current =currentYear+"-"+currentMonth+"-"+p(currentDate);
    return current;
}


function getlastmonth() {
var currentYear=new Date().getFullYear();
var currentMonth=new Date().getMonth()+1;  
var lastMonth=new Date().getMonth();
var currentDate=new Date().getDate();
    var prevCurrentYear=0;
    var prevCurrentMonth=0;
    if(currentMonth==0){
        prevCurrentYear=currentYear-1;
        prevCurrentMonth=12;
    }else{
        prevCurrentYear=currentYear;
        prevCurrentMonth=currentMonth-1;
    }
    var lastmonth=prevCurrentYear+"-"+prevCurrentMonth+"-"+p(currentDate)
    return lastmonth;
}