function inicializeCalendar() {
	$(function(){
	    // Datepicker
	    $.datepicker.setDefaults({
	        showOn: 'both',
	        buttonImage: '',
	        buttonImageOnly: true,
	        buttonText: '',
	        minDate: new Date(),
			beforeShow: function(input) {
			   var input = $(input);
			   input.datepicker('option','oldDate',input.datepicker('getDate'));
			},
	        onSelect: function(dateText, inst) {
	           if(inst.settings.calendarObjectTo!=null) {                          
	              var fromDate = (new Date(inst.selectedYear,inst.selectedMonth,inst.selectedDay));                                                                           
	              var calendarTo = inst.settings.calendarObjectTo;
				  var toDate =  calendarTo.datepicker('getDate');
				  var oldDate =  inst.settings.oldDate;
	              calendarTo.datepicker('option','minDate', fromDate);
				  if(toDate!=null && oldDate!=null) {
	                calendarTo.datepicker('setDate', new Date(toDate.getTime() + (fromDate.getTime() - oldDate.getTime())));                          
	                inst.settings.maxDate = calendarTo.datepicker('getDate');
				  }	
	           }else if (inst.settings.calendarObjectFrom!=null) {                          
	              var calendarFrom = inst.settings.calendarObjectFrom;
	              var dateFrom = calendarFrom.datepicker('getDate');
	              var dateTo = (new Date(inst.selectedYear,inst.selectedMonth,inst.selectedDay));
	              var interval = inst.settings.calendarFromMaxInterval * 86400000;
	              calendarFrom.datepicker('option','maxDate', dateTo);
	              if(dateFrom== null || dateTo - dateFrom.getTime() > interval) {
	                calendarFrom.datepicker('setDate', new Date(dateTo.getTime() - interval));                          
	              }                            
	              inst.settings.minDate = calendarFrom.datepicker('getDate');
	           }
	        }
	    });
	});	
	
	$("#calendarOd").datepicker({
        calendarObjectTo: $("#calendarDo"),
        maxDate: $("#calendarDo").datepicker('getDate'),
        showDown: false
	});

	$("#calendarDo").datepicker({
        calendarObjectFrom: $("#calendarOd"),
        minDate: $("#calendarOd").datepicker('getDate'),
        calendarFromMaxInterval: 36,
        showDown: false
	});
}

/*
 * funkcia pre zobrazenie kalendara pri kliku na ikonku
 */
function clickCalendarDo() {
	$('#calendarDo').focus();		 	 
} 

/*
 * funkcia pre zobrazenie kalendara pri kliku na ikonku
 */
function clickCalendarOd() {
	$('#calendarOd').focus();
}