JS根据出生日期计算年龄

<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>Document</title></head><body> <script language=javascript> function getAge(strAge) { var birArr = strAge.split("-"); var birYear = birArr[0]; var birMonth = birArr[1]; var birDay = birArr[2]; d = new Date(); var nowYear = d.getFullYear(); var nowMonth = d.getMonth() + 1; //记得加1 var nowDay = d.getDate(); var returnAge; if (birArr == null) { return false }; var d = new Date(birYear, birMonth - 1, birDay); if (d.getFullYear() == birYear && (d.getMonth() + 1) == birMonth && d.getDate() == birDay) { if (nowYear == birYear) { returnAge = 0; // } else { var ageDiff = nowYear - birYear; // if (ageDiff > 0) { if (nowMonth == birMonth) { var dayDiff = nowDay - birDay; // if (dayDiff < 0) { returnAge = ageDiff - 1; } else { returnAge = ageDiff; } } else { var monthDiff = nowMonth - birMonth; // if (monthDiff < 0) { returnAge = ageDiff - 1; } else { returnAge = ageDiff; } } } else { 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 } } return returnAge; } else { return ("输入的日期格式错误！"); } } //当前日期 2019-06-05 console.log(getAge("2000-03-22")); //["1980", "03", "22"] ——————19岁 console.log(getAge("2000-06-02")); //["1980", "06", "02"]——————19岁 console.log(getAge("2000-06-12")); //["1980", "06", "12"]——————18岁 console.log(getAge("2002-36-02")); //输入的日期格式错误！ console.log(getAge("2022-02-02")); //出生日期晚于今天，数据有误 </script></body></html>