Hi Dev Ashish,

Unfortunately, WebCalendar still not support disabling specific date. But you could adopt this hack technique by running the following javascript on WebCalendar OnAfterRender ClientSideEvents:

function EnableOnlyDateRange(WebCalendar, fromDate, toDate)        {
            var a = document.querySelectorAll("#" + WebCalendar.ID + "_f td[unselectable = 'on']");
            if (fromDate)
            {
                fromDate.setHours(0, 0, 0, 0);
            }
            if (toDate)
            {
                toDate.setHours(0, 0, 0, 0);
            }
            for (var i = 0; i < a.length; i++)
            {
                var dateDay = new Date(a[i].getAttribute("y"), a[i].getAttribute("m") - 1, a[i].getAttribute("d"));
                if ((fromDate && dateDay < fromDate) || (toDate && dateDay > toDate))
                {
                    a[i].setAttribute("class", WebCalendar.OutboundCellStyle);
                    a[i].setAttribute("cssname", WebCalendar.OutboundCellStyle);
                    a[i].onclick = function () { event.stopPropagation(); };
                }
            }
        }

To make the disabled date(outbound date) look different, you could simply change it through WebCalendar OutboundCellStyle property.

As a reference, I have attach a simple working sample. Please have the sample evaluated on your end by adding it to WebEssentials sample which is included in the installation folder.

Best Regards,
Leo