js 根据出生日期年月日计算年龄

 1 <!DOCTYPE html>
 2 <html>
 3 
 4 <head>
 5   <meta charset="utf-8">
 6   <title></title>
 7 </head>
 8 
 9 <body>
10   <h1></h1>
11 </body>
12 
13 </html>
14 <script language=javascript>
15   function getAge(strAge) {
16       const birArr = strAge.split("-");
17       const birYear = Number(birArr[0]);
18       const birMonth = Number(birArr[1]);
19       const birDay = Number(birArr[2]);
20 
21       const today = new Date();
22       const nowYear = today.getFullYear();
23       const nowMonth = today.getMonth() + 1; //记得加1
24       const nowDay = today.getDate();
25       let returnAge;
26 
27       if (birArr === null) {
28           return false
29       };
30       const d = new Date(birYear, birMonth - 1, birDay);
31       console.log(d.getFullYear(), birYear, (d.getMonth() + 1), birMonth, d.getDate(), birDay);
32       if (d.getFullYear() === birYear && (d.getMonth() + 1) === birMonth && d.getDate() === birDay) {
33           if (nowYear === birYear) {
34               returnAge = 0; // 
35           } else {
36               let ageDiff = nowYear - birYear; // 
37               if (ageDiff > 0) {
38                   if (nowMonth === birMonth) {
39                       let dayDiff = nowDay - birDay; // 
40                       if (dayDiff < 0) {
41                           returnAge = ageDiff - 1;
42                       } else {
43                           returnAge = ageDiff;
44                       }
45                   } else {
46                       let monthDiff = nowMonth - birMonth; // 
47                       if (monthDiff < 0) {
48                           returnAge = ageDiff - 1;
49                       } else {
50                           returnAge = ageDiff;
51                       }
52                   }
53               } else {
54                   return  "出生日期晚于今天，数据有误"; //返回-1 表示出生日期输入错误 晚于今天
55               }
56           }
57           return returnAge;
58       } else {
59           return ("输入的日期格式错误！");
60       }
61   }
62   const age = getAge("2021-07-05")
63   console.log(age);
64   document.getElementsByTagName('h1')[0].innerHTML = age
65 </script>
参考
https://blog.csdn.net/u013746071/article/details/90903997
js 根据出生日期年月日 计算年龄

js 根据出生日期年月日计算年龄
