JavaScript Gregorian Calendar

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Gregorian Calendar in Javascript

    Calendar for  Month:     Year: (Enter a year between 1583 and 25000.)
    Show Calendar for Entire Year (may take a bit of time to appear!)
    Display full calendar in 3x4 format

This script supports Netscape 3.x and 4.x, as well as Internet Explorer 3.x and 4.x. However, there are still a couple of quirks under Netscape 4.x, mainly relating to window resizing. You can try the simpler Java version here if you aren't happy with the output.

To print the generated calendar, use your browser's Print command. For printing, you may like to check the "Display full calendar in 3x4 format" option -- it would save you some paper. Or, to paste it into any HTML-aware application (most word-processors and email clients these days), highlight the calendar, then choose your clipboard Copy command.

About this script

Background

The Gregorian Calendar was introduced by Pope Gregory XIII in 1582, as a correction to the widely followed Julian calendar, when it became apparent that Easter was in grave danger of turning into a Summer festival. With help from the Jesuit astronomer Christoph Clavius (after whom a large moon crater is named), he extended the Julian leap-year concept by saying that years divisible by four but not by 400 were not leap years (1900, 1700, etc. weren't leap years but 2000 is).

This created a calendar without any accuracy problems upto about 33000CE (Common Era, the new politically correct term for AD). However, the Gregorian calendar was initially adopted only in Catholic European countries. So don't expect very early dates generated by this program to match those in national calendars of many countries -- notably Russia (upto 1919) and Britain (upto September 1752). Here is a readable brief history of the development of the Gregorian calendar.

While on Britain, look at what my Linux cal program generates... a decidedly Anglo-centric view of the world, in my opinion.

cs96a2205@linux5 ~$ cal 9 1752
   September 1752
Su Mo Tu We Th Fr Sa
       1  2 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30

Known Issues

In Netscape 3.x/4.x, a new window is opened to show the generated calendar. In some cases (especially in Netscape 4.x), you may not be able to resize the window. Workaround for Netscape 3: Simply maximize the new window. Also, in Netscape 4.x, the month-only calendar appears distended. The Copy/Save As commands work.

Rendering of the generated HTML under Netscape 3.x and IE 3.x has been fixed, but I can't say anything about Netscape 2.x or IE2. Heck, I don't even know where I can get my hands on those antiques!

The 25000 year limit is there for a reason -- many 16-bit machines overflow for larger years. The Gregorian calendar itself requires corrections after 33000CE or so, so you aren't missing much.

History

This is the Javascript version of an applet I originally wrote in Java. Though the JavaScript version can generate prettier output, I have included it on the site for those without JavaScript.

calenJS.html, Dec 12 1998 1354 IST