JS获取上个月与下个月

/*获取上个月*/function getPreMonth(date) {var arr = date.split('-');var year = arr[0]; //获取当前日期的年份var month = arr[1]; //获取当前日期的月份var days = new Date(year, month, 0);days = days.getDate(); //获取当前日期中月的天数var year2 = year;var month2 = parseInt(month) - 1;if (month2 == 0) {year2 = parseInt(year2) - 1;month2 = 12;}var days2 = new Date(year2, month2, 0);days2 = days2.getDate();if (month2 < 10) {month2 = '0' + month2;}var t2 = year2 + '-' + month2;return t2;}/*获取下个月*/function getNextMonth(date) {var arr = date.split('-');var year = arr[0]; //获取当前日期的年份var month = arr[1]; //获取当前日期的月份var days = new Date(year, month, 0);days = days.getDate(); //获取当前日期中的月的天数var year2 = year;var month2 = parseInt(month) + 1;if (month2 == 13) {year2 = parseInt(year2) + 1;month2 = 1;}var days2 = new Date(year2, month2, 0);days2 = days2.getDate();if (month2 < 10) {month2 = '0' + month2;}var t2 = year2 + '-' + month2;return t2;}