CIS 119 Many Date methods/properties

Source code

// Abraham Lincoln's birthday: February 12, 1809
var name = "Abraham Lincoln";
var m = 1;  // January == 0
var d = 12;
var y = 1809;

var daynames = new Array("Sunday", "Monday", "Tuesday",
    "Wednesday", "Thursday", "Friday", "Saturday");
var monthabbr = new Array("Jan", "Feb", "Mar", "Apr", "May",
    "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec");
var monthnames = new Array("January", "February", "March",
    "April", "May", "June", "July", "August", "Sepember",
    "October", "November", "December");

var d1 = new Date(y, m, d);
document.writeln('<h3>Birth Date Information for ' + name + '</h3>');
document.writeln('<p>' + monthnames[m] + ' ' + d + ', ' + y + '</p>');
document.writeln('<p>Month: ' + d1.getMonth() + ' (January = 0) </p>');
document.writeln('<p>Day: ' + d1.getDate() + '</p>');
document.writeln('<p>Year: ' + d1.getFullYear() + '</p>');
document.writeln('<p>Milliseconds since 1/1/1970: ' + d1.getTime() + '</p>');
document.writeln('<p>Day of week: ' + d1.getDay() + '</p>');

document.writeln('<p>-----------------------</p>');
document.writeln('<p>Day name: ' + daynames[d1.getDay()] + '</p>');
document.writeln('<p>Month abbreviation: ' + monthabbr[d1.getMonth()] + '</p>');
document.writeln('<p>Month name: ' + monthnames[d1.getMonth()] + '</p>');

var now = new Date();
if (now.getTime() < d1.getTime()) {
    document.writeln('<p>This person has not been born yet</p>');
} else {
    var daysOld = Math.floor((now.getTime() - d1.getTime()) / (1000 * 60 * 60 * 24));
    document.writeln('<p>This person is ' + daysOld + ' days old</p>');
    var yearsOld = now.getFullYear() - d1.getFullYear();
    if ((now.getMonth() < d1.getMonth()) ||
        ((now.getMonth() == d1.getMonth()) && (now.getDate() < d1.getDate()))) {
        yearsOld--;
    }
    document.writeln('<p>This person is (or would be) ' + yearsOld + ' years old.</p>');
}