时间加减函数

//日期加上天数后的新日期.
function AddDays(date,days){
var nd = new Date(date);
   nd = nd.valueOf();
   nd = nd + days * 24 * 60 * 60 * 1000;
   nd = new Date(nd);
   //alert(nd.getFullYear() + "年" + (nd.getMonth() + 1) + "月" + nd.getDate() + "日");
var y = nd.getFullYear();
var m = nd.getMonth()+1;
var d = nd.getDate();
if(m <= 9) m = "0"+m;
if(d <= 9) d = "0"+d; 
var cdate = y+"-"+m+"-"+d;
return cdate;
}
//两个日期的差值(d1 - d2).
function DateDiff(d1,d2){
    var day = 24 * 60 * 60 *1000;
try{    
        var dateArr = d1.split("-");
   var checkDate = new Date();
        checkDate.setFullYear(dateArr[0], dateArr[1]-1, dateArr[2]);
   var checkTime = checkDate.getTime();
  
   var dateArr2 = d2.split("-");
   var checkDate2 = new Date();
        checkDate2.setFullYear(dateArr2[0], dateArr2[1]-1, dateArr2[2]);
   var checkTime2 = checkDate2.getTime();
    
   var cha = (checkTime - checkTime2)/day;  
        return cha;
    }catch(e){
   return false;
}
}//end fun