diff -urN org/reports.toptriggers.js.php new/reports.toptriggers.js.php
--- org/reports.toptriggers.js.php	2014-12-25 16:43:28.000000000 +0900
+++ new/reports.toptriggers.js.php	2014-12-26 11:05:34.000000000 +0900
@@ -6,128 +6,66 @@
 	 */
 	function setPeriod(period) {
 		var date = new Date(),
+			fr_date, to_date,
 			newPeriod = [];
 
 		switch (period) {
 			case <?php echo REPORT_PERIOD_TODAY; ?>:
-				newPeriod = {
-					'fromYear': date.getFullYear(),
-					'fromMonth': date.getMonth() + 1,
-					'fromDay': date.getDate(),
-					'tillYear': date.getFullYear(),
-					'tillMonth': date.getMonth() + 1,
-					'tillDay': date.getDate() + 1
-				}
+				fr_date = date;
+				to_date = computeDate(date.getFullYear(), date.getMonth() + 1, date.getDate(), 1);
 				break;
 
 			case <?php echo REPORT_PERIOD_YESTERDAY; ?>:
-				date.setTime(date.getTime() - <?php echo SEC_PER_DAY; ?> * 1000);
-
-				newPeriod = {
-					'fromYear': date.getFullYear(),
-					'fromMonth': date.getMonth() + 1,
-					'fromDay': date.getDate(),
-					'tillYear': date.getFullYear(),
-					'tillMonth': date.getMonth() + 1,
-					'tillDay': date.getDate() + 1
-				}
+				fr_date = computeDate(date.getFullYear(), date.getMonth() + 1, date.getDate(), -1);
+				to_date = date;
 				break;
 
 			case <?php echo REPORT_PERIOD_CURRENT_WEEK; ?>:
 				var weekBegin = date.getTime() - (date.getDay() - 1) * <?php echo SEC_PER_DAY; ?> * 1000,
 					weekEnd = weekBegin + <?php echo SEC_PER_DAY; ?> * 1000 * 7,
-					dateFrom = new Date(date.setTime(weekBegin)),
-					dateTill = new Date(date.setTime(weekEnd));
-
-				newPeriod = {
-					'fromYear': dateFrom.getFullYear(),
-					'fromMonth': dateFrom.getMonth() + 1,
-					'fromDay': dateFrom.getDate(),
-					'tillYear': dateTill.getFullYear(),
-					'tillMonth': dateTill.getMonth() + 1,
-					'tillDay': dateTill.getDate()
-				}
+					fr_date = new Date(date.setTime(weekBegin)),
+					to_date = new Date(date.setTime(weekEnd));
 				break;
 
 			case <?php echo REPORT_PERIOD_CURRENT_MONTH; ?>:
-				newPeriod = {
-					'fromYear': date.getFullYear(),
-					'fromMonth': date.getMonth() + 1,
-					'fromDay': '1',
-					'tillYear': date.getFullYear(),
-					'tillMonth': date.getMonth() + 2,
-					'tillDay': '1'
-				}
+				fr_date = new Date(date.getFullYear(), date.getMonth(), 1);
+				to_date = computeMonth(date.getFullYear(), date.getMonth() + 1, 1, 1);
 				break;
 
 			case <?php echo REPORT_PERIOD_CURRENT_YEAR; ?>:
-				newPeriod = {
-					'fromYear': date.getFullYear(),
-					'fromMonth': '1',
-					'fromDay': '1',
-					'tillYear': date.getFullYear() + 1,
-					'tillMonth': '1',
-					'tillDay': '1'
-				}
+				fr_date = new Date(date.getFullYear(), 0, 1);
+				to_date = new Date(date.getFullYear() + 1, 0, 1);
 				break;
 
 			case <?php echo REPORT_PERIOD_LAST_WEEK; ?>:
 				var lastWeekBegin = date.getTime() + ( - date.getDay() - 6) * <?php echo SEC_PER_DAY; ?> * 1000,
 					lastWeekEnd = lastWeekBegin + <?php echo SEC_PER_DAY; ?> * 1000 * 7,
-					dateFrom = new Date(date.setTime(lastWeekBegin)),
-					dateTill = new Date(date.setTime(lastWeekEnd));
-
-				newPeriod = {
-					'fromYear': dateFrom.getFullYear(),
-					'fromMonth': dateFrom.getMonth() + 1,
-					'fromDay': dateFrom.getDate(),
-					'tillYear': dateTill.getFullYear(),
-					'tillMonth': dateTill.getMonth() + 1,
-					'tillDay': dateTill.getDate()
-				}
+					fr_date = new Date(date.setTime(lastWeekBegin)),
+					to_date = new Date(date.setTime(lastWeekEnd));
 				break;
 
 			case <?php echo REPORT_PERIOD_LAST_MONTH; ?>:
-				if (date.getMonth() == 0) {
-					// 11 month is december
-					date = new Date(date.getFullYear() - 1, 11, 31);
-				}
-				else {
-					date = new Date(date.getFullYear(), date.getMonth() - 1,
-						daysInMonth(date.getFullYear(), date.getMonth() - 1)
-					);
-				}
-
-				newPeriod = {
-					'fromYear': date.getFullYear(),
-					'fromMonth': date.getMonth() + 1,
-					'fromDay': '1',
-					'tillYear': date.getFullYear(),
-					'tillMonth': date.getMonth() + 2,
-					'tillDay': '1'
-				}
+				fr_date = computeMonth(date.getFullYear(), date.getMonth() + 1, 1, -1);
+				to_date = new Date(date.getFullYear(), date.getMonth(), 1);
 				break;
 
 			case <?php echo REPORT_PERIOD_LAST_YEAR; ?>:
-				newPeriod = {
-					'fromYear': date.getFullYear() - 1,
-					'fromMonth': '1',
-					'fromDay': '1',
-					'tillYear': date.getFullYear(),
-					'tillMonth': '1',
-					'tillDay': '1'
-				}
+				fr_date = new Date(date.getFullYear() - 1, 0, 1);
+				to_date = new Date(date.getFullYear(), 0, 1);
 				break;
 
 			default:
-				newPeriod = {
-					'fromYear': date.getFullYear(),
-					'fromMonth': date.getMonth() + 1,
-					'fromDay': date.getDate(),
-					'tillYear': date.getFullYear(),
-					'tillMonth': date.getMonth() + 1,
-					'tillDay': date.getDate() + 1
-				}
+				fr_date = date;
+				to_date = computeDate(date.getFullYear(), date.getMonth() + 1, date.getDate(), 1);
+		}
+
+		newPeriod = {
+			'fromYear': fr_date.getFullYear(),
+			'fromMonth': fr_date.getMonth() + 1,
+			'fromDay': fr_date.getDate(),
+			'tillYear': to_date.getFullYear(),
+			'tillMonth': to_date.getMonth() + 1,
+			'tillDay': to_date.getDate() 
 		}
 
 		updatePeriod(newPeriod);
@@ -168,4 +106,48 @@
 		jQuery('#filter_from').val(data.fromYear+''+data.fromMonth+''+data.fromDay+'000000');
 		jQuery('#filter_till').val(data.tillYear+''+data.tillMonth+''+data.tillDay+'000000');
 	}
+
+	/**
+	 *  get the last day of the month.
+	 * 
+	 *  @param int year
+	 *  @param int month
+	 */
+	function getMonthEndDay(year, month) {
+		var dt = new Date(year, month, 0);
+		return dt.getDate();
+	}
+
+	/**
+	 *  number of days add or subtract.
+	 * 
+	 *  @param int year
+	 *  @param int month
+	 *  @param int day
+	 *  @param int addDays
+	 */
+	function computeDate(year, month, day, addDays) {
+		var dt = new Date(year, month - 1, day);
+		var baseSec = dt.getTime();
+		var addSec = addDays * 86400000;
+		var targetSec = baseSec + addSec;
+		dt.setTime(targetSec);
+		return dt;
+	}
+
+	/**
+	 *  number of month add or subtract.
+	 * 
+	 *  @param int year
+	 *  @param int month
+	 *  @param int day
+	 *  @param int addMonths
+	 */
+	function computeMonth(year, month, day, addMonths) {
+		month += addMonths;
+		var endDay = getMonthEndDay(year, month);
+		if(day > endDay) day = endDay;
+		var dt = new Date(year, month - 1, day);
+		return dt;
+	}
 </script>