dp.onBeforeCellRender = function(args) { if (args.cell.start.getDayOfWeek() == 7) { // does not work but == 6 or 5 or 4... it work args.cell.backColor = "#EDED9F"; } };
DayPilot.Date.getDayOfWeek() returns 0 for Sunday, 1 for Monday ... 6 for Saturday:
https://api.daypilot.org/daypilot-date-getdayofweek/