Disable days in jQuery Datepicker depend on other properties in model MVC

I want to disable specific days of the week in jQuery UI DatePicker , depending on whether a value is true or false in the model submitted in @razor view . I have a bool for each weekday . If a value is constructed so will the day be available in datepickern but if false, then the day will be disabled. I looked around on different sides here but none of these options worked for me . Here is my code : $('#txtStartDate').datepicker({ defaultDate: '+1w', numberOfMonths: 1, showAnim: 'slide', changeMonth: true, changeYear: true, showWeek: true, dateFormat: "yy-mm-dd", minDate: new Date(hidStartDate), beforeShowDay: function(date) { var day = date.getDay(); if (day == 1 && $('#hidMonday').val() == "True") { return day; } if (day == 2 && $('#hidTuesday').val() == "True") { return day; } if (day == 3 && $('#hidWednesday').val() == "True") { return day; } if (day == 4 && $('#hidThursday').val() == "True") { return day; } if (day == 5 && $('#hidFriday').val() == "True") { return day; } }, }); $('#txtStartDate').css('clip', 'auto'); Once it has gone through about 5-6 days in the calendar , I get the following error in the console " Jquery - ui.js : 9742 uncaught TypeError : Can not read property '0' of undefined ". That said , I have looked around on the solution proposed here , but it may not work. This solution is based on the following proposal: Disable specific days of the week on jQuery UI datepicker Thanks in advance.