Calculate Birthdate From Given Age

As there was a requirement in my project to calculate birthdate from age(Age in Year,Age in Month,Age in days) given.

I have created one function in javascript which will give the birthdate in dd/mm/yyyy format.
The function is as given below.

1 function CalculateBirthDateFromAge(AgeInYear,AgeInMonth,AgeInDays)
2 {
4 var currentDate=new Date();
5 var getCMonth=(currentDate.getMonth()); //Get current month
6 var getCYear=currentDate.getFullYear(); //Get current Year
7 var getCDate=currentDate.getDate(); //Get Current Date
8 var getAgeInDays = AgeInDays;
9 var getAgeInMonth = AgeInMonth;
10 var getAgeInYear = AgeInYear;
12 var yd = getCYear;
13 var md = getCMonth +1 ;
14 var mLength ="0";
15 var mon=0;
16 var mb=0;
17 var yb=0;
18 var db
19 if(getAgeInDays!="")
20 {
21 db = getCDate-getAgeInDays;
22 var g31Day=new Array(1,3,5,7,8,10,12);
26 var g30Day=new Array(2,4,6,9,11);
27 var gMonth=12;
28 var gDay=0;
29 var getCurentMont=(getCMonth +1 );//get current month
30 var getCurrentYear=getCYear;//get current year
31 for(var i=0;i < g31Day.length;i++)
33{
34 if (g31Day[i]== (getCurentMont))
35{
36 gDay=31;
37 break;
38 }
39 }
41 if(gDay==0)
42{
43 for(var i=0;i < g30Day.length; i++)
44{
45 if(g30Day[i] == getCurentMont)
47 {
48 if(getCurentMont==2)
49{
50 if(getCurrentYear % 4 == 0 (getCurrentYear % 100 != 0 && getCurrentYear % 4 == 0))
51{
52 gDay=29;
53 break;
54 }
55 else
56{
57 gDay=28;
58 break;
59 }
61 }
62 else
63{
64 gDay=30;
65 break;
66 }
67 }
68 }
69 }
73 if( db <= 0)
74{
76 db=db+ parseInt(gDay);
77 }
80}
81else
82db=01;
85 if(getAgeInMonth!="")
86 mb = md -getAgeInMonth;//month
87 else
88 mb = 01;//month
89 if(mb <= 0)
91 {
92 yd--;
93 mb=mb+12;
94 }
96if(getAgeInYear!="")
97 yb = yd - getAgeInYear;
98 else
99 yb =getCYear;
100 alert("My BirthDate Is "+db+"/"+mb+"/"+yb);
101 }

You have to pass the Age in years,age in month and age in days as Parameters to the given function.