code: function(year) {
      var a = year % 19;
      var b = Math.floor(year / 100);
      var c = year % 100;
      var d = Math.floor(b / 4);
      var e = b % 4;
      var f = Math.floor((b + 8) / 25);
      var g = Math.floor((b - f + 1) / 3);
      var h = (19 * a + b - d - g + 15) % 30;
      var i = Math.floor(c / 4);
      var k = c % 4;
      var l = (32 + 2 * e + 2 * i - h - k) % 7;
      var m = Math.floor((a + 11 * h + 22 * l) / 451);
      var n0 = h + l + 7 * m + 114;
      var n = Math.floor(n0 / 31) - 1;
      var p = n0 % 31 + 1;
      var date = this.createDate(year, n + 1, p);
      return date;
    }
docs: Determines the date of Easter Sunday.
  @param {number} year
  @return {Date}