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//	-------------------------------------------------------------------------
//
//	Date of Easter Sunday in a given year
if	(! Date.prototype.Easter)
{
	Date.prototype.Easter	= 
		function()
		{
			// Algorithm optimised from 'Puzzles and Paradoxes' by T H O'Beirne 
			// (Oxford University Press, London (c) 1965)
			var	year	= this.getFullYear();
			var	a	= year % 19;
			var	b	= Math.floor(year / 100);
			var	c	= year % 100;
			var	d	= Math.floor(b / 4);
			var	h	= (19 * a + b - d - Math.floor((8 * b + 13) / 25) + 15) % 30;
			var	mu	= Math.floor((a + 11 * h) / 319) - h;
			var	lambda	= (2 * (b - d * 4) + Math.floor(c / 4) * 6 - c + mu + 32) % 7 - mu;
			var	month	= Math.floor((lambda + 90) / 25);

			return	new Date(year, month - 1, (lambda + month + 19) % 32);
		};	// Date.prototype.Easter

	Date.Easter	= function(optYear) { return (new Date(optYear)).Easter(); };
}	// if		
//
//	-------------------------------------------------------------------------

chriselst wrote:

Although my code (not really my code, I borrowed it initially) did fail in Easter 2013 when it attempted to set Easter Monday as the 32nd of March.