原生JS获取日期[当前日期/指定日期 + 天数]

function GetDateStr(AddDayCount){
    var dd = new Date();
    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();
    if(m < 10) m = '0'+m;
    return y+"-"+m+"-"+d;
}

function GetDateStr(AddDayCount,AddMonthCount){
    var dd = new Date();
    dd.setMonth(dd.getMonth()+AddMonthCount);
    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();
    if(m < 10) m = '0'+m;
    if(d < 10) d = '0'+d;
    return y+"-"+m+"-"+d;
}

function dateAdd(startDate,day){
    startDate = new Date(startDate);
    startDate = +startDate + 1000 * 60 * 60 * 24 * day;
    startDate = new Date(startDate);
    var nextStartDate = startDate.getFullYear() + "-" + (startDate.getMonth() + 1) + "-" + startDate.getDate() + ' '+startDate.getHours() + ':' + startDate.getMinutes() + ':' + startDate.getSeconds();
    return nextStartDate;
}