js根据生日计算出年龄

1. /*根据出生日期算出年龄*/  
2. function jsGetAge(strBirthday){         
3.     var returnAge;  
4.     var strBirthdayArr=strBirthday.split("-");  
5.     var birthYear = strBirthdayArr[0];  
6.     var birthMonth = strBirthdayArr[1];  
7.     var birthDay = strBirthdayArr[2];  
8.       
9.     d = new Date();  
10.     var nowYear = d.getFullYear();  
11.     var nowMonth = d.getMonth() + 1;  
12.     var nowDay = d.getDate();  
13.       
14.     if(nowYear == birthYear){  
15.         returnAge = 0;//同年 则为0岁  
16.     }  
17.     else{  
18.         var ageDiff = nowYear - birthYear ; //年之差  
19.         if(ageDiff > 0){  
20.             if(nowMonth == birthMonth) {  
21.                 var dayDiff = nowDay - birthDay;//日之差  
22.                 if(dayDiff < 0)  
23.                 {  
24.                     returnAge = ageDiff - 1;  
25.                 }  
26.                 else  
27.                 {  
28.                     returnAge = ageDiff ;  
29.                 }  
30.             }  
31.             else  
32.             {  
33.                 var monthDiff = nowMonth - birthMonth;//月之差  
34.                 if(monthDiff < 0)  
35.                 {  
36.                     returnAge = ageDiff - 1;  
37.                 }  
38.                 else  
39.                 {  
40.                     returnAge = ageDiff ;  
41.                 }  
42.             }  
43.         }  
44.         else  
45.         {  
46.             returnAge = -1;//返回-1 表示出生日期输入错误 晚于今天  
47.         }  
48.     }  
49.       
50.     return returnAge;//返回周岁年龄  
51.       
52. }