Thanks for the reply. But what I wants to do is change the selected day in my SelectionChanging event. Because once SelectionChanging occur, I’m adding a custom day with a style. In the second selection I will be able to add another custom day with different style to the same day. Therefore I need to change the selected day in my SelectionChanging event. I tried, but not succeeded. Below is my code.

<script type="text/javascript">

function ChangeSelection(sender, args) {

            if (document.getElementById("txtHiddenHolidayType").value != null) {

                var Date = sender.get_selectedRange();

                if (Date != null) {

                    var selectedType = document.getElementById("txtHiddenHolidayType").value;

                    var style = GetSelectedStyle(selectedType);

                    document.getElementById("txtHiddenSelectedDate").value = document.getElementById("txtHiddenSelectedDate").value + Date;

                    var arr = new Array();

                    var arr2 = new Array();

                    arr = document.getElementById("txtHiddenSelectedDate").value.split(",");

                    for (var i = 0; i < arr.length; i++) {

                        arr2 = arr[i].split(" ");

                        var selectedDayName = arr2[0];

                        var selectedMonthName = arr2[1];

                        var selectedMonth = FindMonth(selectedMonthName);

                        var selectedDay = arr2[2];

                        var selectedYear = arr2[5];

                        var strDate_Style = selectedDayName + " " + selectedMonthName + " " + selectedDay + " " + "xx" + " " + "xxx" + " " + selectedYear + "#" + selectedType + "%";

                        document.getElementById("txtHiddenDateCollection").value = document.getElementById("txtHiddenDateCollection").value + strDate_Style;

                        $find(sender._id).addCustomDay(selectedYear, selectedMonth, selectedDay, "", "", "", style);

                    }

                }

            }

        }

</script>

<ig:WebMonthCalendar ID="WebMonthCalendar2" runat="server" DayNameFormat="FirstLetter"

                                    EnableWeekNumbers="True" FirstDayOfWeek="Monday" Height="150px" HideOtherMonthDays="True"

                                    SelectionType="Multi" ShowNextPrevMonth="False" Width="200px" FooterContent=""

                                    TitleFormat="Month" ShowFooter="False" StyleSetPath="../ig_calendar2.css" CellSpacing="1"

                                    EnableMonthDropDown="False" EnableYearDropDown="False">

                                    <ClientEvents SelectionChanging="GetSelectedDate" SelectionChanged="ChangeSelection" />

                                </ig:WebMonthCalendar>