.everyThirdDay { background-color: gray; } .weekendBold { font-weight: bold; font-style: italic; } var curDt = new Date(); function disablementFunction(day){ if (day.isWeekend) return false; if (curDt==undefined){ curDt = day.date.getDate(); } if (curDt.getTime() - day.date.getTime() < 0) return true; else return false; } function disabledClassesProv(day){ if (curDt.getTime() - day.date.getTime() >= 0) return 'rf-cal-boundary-day'; var res = ''; if (day.isWeekend) res+='weekendBold '; if (day.day%3==0) res+='everyThirdDay'; return res; }