javascript - Age calculation
function getAge(dateString) {
var now = new Date();
var today = new Date(now.getYear(),now.getMonth(),now.getDate());
var yearNow = now.getYear();
var monthNow = now.getMonth();
var dateNow = now.getDate();
var dob = new Date(dateString.substring(6,10),
dateString.substring(0,2)-1,
dateString.substring(3,5)
);
var yearDob = dob.getYear();
var monthDob = dob.getMonth();
var dateDob = dob.getDate();
var age = {};
var ageString = "";
var yearString = "";
var monthString = "";
var dayString = "";
yearAge = yearNow - yearDob;
if (monthNow >= monthDob)
var monthAge = monthNow - monthDob;
else {
yearAge--;
var monthAge = 12 + monthNow -monthDob;
}
if (dateNow >= dateDob)
var dateAge = dateNow - dateDob;
else {
monthAge--;
var dateAge = 31 + dateNow - dateDob;
if (monthAge < 0) {
monthAge = 11;
yearAge--;
}
}
age = {
years: yearAge,
months: monthAge,
days: dateAge
};
if ( age.years > 1 ) yearString = " years";
else yearString = " year";
if ( age.months> 1 ) monthString = " months";
else monthString = " month";
if ( age.days > 1 ) dayString = " days";
else dayString = " day";
if ( (age.years > 0) && (age.months > 0) && (age.days > 0) )
ageString = age.years + yearString + ", " + age.months + monthString + ", and " + age.days + dayString + " old.";
else if ( (age.years == 0) && (age.months == 0) && (age.days > 0) )
ageString = "Only " + age.days + dayString + " old!";
else if ( (age.years > 0) && (age.months == 0) && (age.days == 0) )
ageString = age.years + yearString + " old. Happy Birthday!!";
else if ( (age.years > 0) && (age.months > 0) && (age.days == 0) )
ageString = age.years + yearString + " and " + age.months + monthString + " old.";
else if ( (age.years == 0) && (age.months > 0) && (age.days > 0) )
ageString = age.months + monthString + " and " + age.days + dayString + " old.";
else if ( (age.years > 0) && (age.months == 0) && (age.days > 0) )
ageString = age.years + yearString + " and " + age.days + dayString + " old.";
else if ( (age.years == 0) && (age.months > 0) && (age.days == 0) )
ageString = age.months + monthString + " old.";
else ageString = "Oops! Could not calculate age!";
return ageString;
}
// A bit of jQuery to call the getAge() function and update the page...
$(document).ready(function() {
$("#submitDate").click(function(e) {
e.preventDefault();
$("#age").html(getAge($("input#date").val()));
});
});
and HTML IS
Date (MM/DD/YYYY): Calculate Age
Age: 7 years, 1 month, and 15 days old.function calculateAge (birthDate, otherDate) {
birthDate = new Date(birthDate);
otherDate = new Date(otherDate);
var years = (otherDate.getFullYear() - birthDate.getFullYear());
if (otherDate.getMonth() < birthDate.getMonth() ||
otherDate.getMonth() == birthDate.getMonth() && otherDate.getDate() < birthDate.getDate()) {
years--;
}
return years;
}
Example:
var age = calculateAge("02/24/1991", "02/24/2010"); // Format: MM/DD/YYYY
Here is a way:
function getAge(d1, d2){
d2 = d2 || new Date();
var diff = d2.getTime() - d1.getTime();
return Math.floor(diff / (1000 * 60 * 60 * 24 * 365.25));
}
console.log( getAge(new Date(1978, 10, 3)) );
Be careful with the month. Javascript counts them from 0.1978, 10, 3
means the November 3th, 1978
Convert the date to milliseconds since the epoch using getTime(), then subtract the values and convert the result back to years:
const MS_PER_YEAR = 1000 * 60 * 60 * 24 * 365.2425;
var years = Math.floor((dateNow.getTime() - dateThen.getTime()) / MS_PER_YEARS);