AddDate function

/* ----------------------------------------------------------------

AddDate([date:Array], datePart:string, Add_Number:number);

date =[dd, mm, yyyy, hours, Minutes,Seconds, Milliseconds]
datePart = d:Days
mo:Month
y:Year
h:Hours
mi:Minutes
s:Seconds
ms:Milliseconds

Example: alert(AddDate([28,2,2009], "d", 1)); // outupt: Sun Mar 1 11:44:38 UTC+0530 2009
alert(AddDate([28,2,2009], "y", 1)); // outupt: Sun Mar 1 11:44:38 UTC+0530 2010
---------------------------------------------------------------- */
Date.prototype.add = function (datePart, Num){
var TmpDate = this;
if (!datePart || Num == 0) return TmpDate;
switch (datePart.toLowerCase()){
case "ms":
TmpDate.setMilliseconds(TmpDate.getMilliseconds() + Num);
break;
case "s":
TmpDate.setSeconds(TmpDate.getSeconds() + Num);
break;
case "mi":
TmpDate.setMinutes(TmpDate.getMinutes() + Num);
break;
case "h":
TmpDate.setHours(TmpDate.getHours() + Num);
break;
case "d":
TmpDate.setDate(TmpDate.getDate() + Num);
break;
case "mo":
TmpDate.setMonth(TmpDate.getMonth() + Num);
break;
case "y":
TmpDate.setFullYear(TmpDate.getFullYear() + Num);
break;
}
return TmpDate;
}

function AddDate(InputDate1, datePart, Num){
var d = new Date();
if(InputDate1[0]!=undefined){
d.setDate(InputDate1[0]);
}
if(InputDate1[1]!=undefined){
d.setMonth(InputDate1[1]-1);
}
if(InputDate1[2]!=undefined){
d.setYear(InputDate1[2]);
}
if(InputDate1[3]!=undefined){
d.setHours(InputDate1[3]);
}
if(InputDate1[4]!=undefined){
d.setMinutes(InputDate1[4]);
}
if(InputDate1[5]!=undefined){
d.setSeconds(InputDate1[5]);
}
if(InputDate1[6]!=undefined){
d.setMilliseconds(InputDate1[6]);
}
return d.add(datePart, Num)
}

//use of this function
var d22 = new Date();
d22 = AddDate([28,2,2009], "d", 1);
alert(d22);