I tried the following client side code in order to check whether any appointment is inserted for the day and cancel in new insert event if there is any already inserted.
JavaScript:
<script type="text/javascript">
function OnClientAppointmentInserting(sender, args)
{
var num = sender.get_appointments().get_count();
for( var i = 0; i<num; i++)
{
var tempDate = sender.get_appointments().getAppointment(i).get_start().localeFormat('MM/dd/yyyy');