如果给出格式为YYYYMMDD的出生日期，如何以年计算年龄?是否可以使用Date()函数?
我正在寻找一个比我现在使用的更好的解决方案:
Var dob = '19800810'; var年=数字(dob.)substr (0, 4)); var月=数字(dob.)Substr (4, 2)) - 1; var day =数字(dob.)2) substr(6日); var today = new Date(); var age = today.getFullYear() -年份; if (today.getMonth() < month || (today.getMonth() == month && today.getDate() < day)) { 年龄——; ｝ 警报(年龄);
当前回答
不久前，我做了一个这样的函数:
function getAge(birthDate) {
var now = new Date();
function isLeap(year) {
return year % 4 == 0 && (year % 100 != 0 || year % 400 == 0);
}
// days since the birthdate
var days = Math.floor((now.getTime() - birthDate.getTime())/1000/60/60/24);
var age = 0;
// iterate the years
for (var y = birthDate.getFullYear(); y <= now.getFullYear(); y++){
var daysInYear = isLeap(y) ? 366 : 365;
if (days >= daysInYear){
days -= daysInYear;
age++;
// increment the age only if there are available enough days for the year.
}
}
return age;
}
它接受一个Date对象作为输入，所以你需要解析'YYYYMMDD'格式的日期字符串:
var birthDateStr = '19840831',
parts = birthDateStr.match(/(\d{4})(\d{2})(\d{2})/),
dateObj = new Date(parts[1], parts[2]-1, parts[3]); // months 0-based!
getAge(dateObj); // 26
其他回答
不久前，我做了一个这样的函数:
function getAge(birthDate) {
var now = new Date();
function isLeap(year) {
return year % 4 == 0 && (year % 100 != 0 || year % 400 == 0);
}
// days since the birthdate
var days = Math.floor((now.getTime() - birthDate.getTime())/1000/60/60/24);
var age = 0;
// iterate the years
for (var y = birthDate.getFullYear(); y <= now.getFullYear(); y++){
var daysInYear = isLeap(y) ? 366 : 365;
if (days >= daysInYear){
days -= daysInYear;
age++;
// increment the age only if there are available enough days for the year.
}
}
return age;
}
它接受一个Date对象作为输入，所以你需要解析'YYYYMMDD'格式的日期字符串:
var birthDateStr = '19840831',
parts = birthDateStr.match(/(\d{4})(\d{2})(\d{2})/),
dateObj = new Date(parts[1], parts[2]-1, parts[3]); // months 0-based!
getAge(dateObj); // 26
重要提示:这个答案并不能提供100%的准确答案，根据日期的不同，它会有10-20个小时的误差。
没有更好的解决方案(至少在这些答案中没有)。——纳文
我当然无法抗拒接受挑战的冲动，制作一个比目前公认的解决方案更快、更短的生日计算器。 我的解决方案的要点是，数学是快速的，所以不是使用分支和javascript提供的日期模型来计算解决方案，我们使用美妙的数学
答案是这样的，运行速度比naveen快65%，而且更短:
function calcAge(dateString) {
var birthday = +new Date(dateString);
return ~~((Date.now() - birthday) / (31557600000));
}
神奇的数字:31557600000等于24 * 3600 * 365.25 * 1000 也就是一年的长度，一年的长度是365天6小时，也就是0.25天。最后，我对结果进行了统计，得出了最终的年龄。
以下是基准测试:http://jsperf.com/birthday-calculation
要支持OP的数据格式，可以替换+new Date(dateString); +新日期(d。Substr (0,4)， d.substr(4,2)-1, d.substr(6,2));
如果你能想出一个更好的解决方案，请分享!：-)
以下是计算年龄的简单方法:
//dob date dd/mm/yy
var d = 01/01/1990
//today
//date today string format
var today = new Date(); // i.e wed 04 may 2016 15:12:09 GMT
//todays year
var todayYear = today.getFullYear();
// today month
var todayMonth = today.getMonth();
//today date
var todayDate = today.getDate();
//dob
//dob parsed as date format
var dob = new Date(d);
// dob year
var dobYear = dob.getFullYear();
// dob month
var dobMonth = dob.getMonth();
//dob date
var dobDate = dob.getDate();
var yearsDiff = todayYear - dobYear ;
var age;
if ( todayMonth < dobMonth )
{
age = yearsDiff - 1;
}
else if ( todayMonth > dobMonth )
{
age = yearsDiff ;
}
else //if today month = dob month
{ if ( todayDate < dobDate )
{
age = yearsDiff - 1;
}
else
{
age = yearsDiff;
}
}
看这个例子，你从这里得到完整的年、月、日信息
function getAge(dateString) {
var today = new Date();
var birthDate = new Date(dateString);
var age = today.getFullYear() - birthDate.getFullYear();
var m = today.getMonth() - birthDate.getMonth();
var da = today.getDate() - birthDate.getDate();
if (m < 0 || (m === 0 && today.getDate() < birthDate.getDate())) {
age--;
}
if(m<0){
m +=12;
}
if(da<0){
da +=30;
}
return age+" years "+ Math.abs(m) + "months"+ Math.abs(da) + " days";
}
alert('age: ' + getAge("1987/08/31"));
[http://jsfiddle.net/tapos00/2g70ue5y/][1]
function change(){
setTimeout(function(){
var dateObj = new Date();
var month = dateObj.getUTCMonth() + 1; //months from 1-12
var day = dateObj.getUTCDate();
var year = dateObj.getUTCFullYear();
var newdate = year + "/" + month + "/" + day;
var entered_birthdate = document.getElementById('birth_dates').value;
var birthdate = new Date(entered_birthdate);
var birth_year = birthdate.getUTCFullYear();
var birth_month = birthdate.getUTCMonth() + 1;
var birth_date = birthdate.getUTCDate();
var age_year = (year-birth_year);
var age_month = (month-birth_month);
var age_date = ((day-birth_date) < 0)?(31+(day-birth_date)):(day-birth_date);
var test = (birth_year>year)?true:((age_year===0)?((month<birth_month)?true:((month===birth_month)?(day < birth_date):false)):false) ;
if (test === true || (document.getElementById("birth_dates").value=== "")){
document.getElementById("ages").innerHTML = "";
} else{
var age = (age_year > 1)?age_year:( ((age_year=== 1 )&&(age_month >= 0))?age_year:((age_month < 0)?(age_month+12):((age_month > 1)?age_month: ( ((age_month===1) && (day>birth_date) ) ? age_month:age_date) ) ));
var ages = ((age===age_date)&&(age!==age_month)&&(age!==age_year))?(age_date+"days"):((((age===age_month+12)||(age===age_month)&&(age!==age_year))?(age+"months"):age_year+"years"));
document.getElementById("ages").innerHTML = ages;
}
}, 30);
};
