日期+天数

function getthedate(dd,dadd){
    //dd为日期，dadd为所加天数
    var a = new Date(dd);
    a = a.valueOf();
    a = a + dadd * 24 * 60 * 60 * 1000;
    a = new Date(a);
    var m = a.getMonth() + 1;
    if(m.toString().length == 1){m=‘0‘+m;}
    var d = a.getDate();
    if(d.toString().length == 1){d=‘0‘+d;}
       return a.getFullYear() + "-" + m + "-" + d;
}