Ticket #4131: datepicker_showWeeks.diff

--- ui.datepicker.js.org	2009-03-20 23:44:27.000000000 +0000
+++ ui.datepicker.js	2009-03-21 00:11:28.000000000 +0000
@@ -77,6 +77,7 @@
 		showOtherMonths: false, // True to show dates in other months, false to leave blank
 		calculateWeek: this.iso8601Week, // How to calculate the week of the year,
 			// takes a Date and returns the number of the week for it
+		showWeekNumbers: false, // True to show week numbers
 		shortYearCutoff: '+10', // Short year values < this are in the current century,
 			// > this are in the previous century,
 			// string value starting with '+' for current year + value
@@ -1321,6 +1322,7 @@
 		var beforeShowDay = this._get(inst, 'beforeShowDay');
 		var showOtherMonths = this._get(inst, 'showOtherMonths');
 		var calculateWeek = this._get(inst, 'calculateWeek') || this.iso8601Week;
+		var showWeek = this._get(inst, 'showWeekNumbers');
 		var endDate = inst.endDay ? this._daylightSavingAdjust(
 			new Date(inst.endYear, inst.endMonth, inst.endDay)) : currentDate;
 		var defaultDate = this._getDefaultDate(inst);
@@ -1347,7 +1349,7 @@
 					selectedDate, row > 0 || col > 0, monthNames, monthNamesShort) + // draw month headers
 					'</div><table class="ui-datepicker-calendar"><thead>' +
 					'<tr>';
-				var thead = '';
+				var thead = showWeek ? '<th><span title="Week number">w</span></th>' : '';
 				for (var dow = 0; dow < 7; dow++) { // days of the week
 					var day = (dow + firstDay) % 7;
 					thead += '<th' + ((dow + firstDay + 6) % 7 >= 5 ? ' class="ui-datepicker-week-end"' : '') + '>' +
@@ -1362,6 +1364,7 @@
 				var printDate = this._daylightSavingAdjust(new Date(drawYear, drawMonth, 1 - leadDays));
 				for (var dRow = 0; dRow < numRows; dRow++) { // create date picker rows
 					calender += '<tr>';
+					if (showWeek) calender += '<td><span>' + calculateWeek(printDate) + '</span></td>';
 					var tbody = '';
 					for (var dow = 0; dow < 7; dow++) { // create date picker days
 						var daySettings = (beforeShowDay ?