datepicker solo al primo click

[Vindav]

prova cosi:

$( "#checkinIframe, #checkoutIframe" ).datepicker({
	dateFormat: 'dd/mm/yy',
	minDate: new Date(<?php echo date("Y"); ?>, <?php echo date("m"); ?> - 1, <?php echo date("d"); ?> ),
	onSelect: function( selectedDate ) {
		if(this.id == "checkinIframe"){
			dataArray = selectedDate.split("/"); 
                        var giornoCheckOut = parseInt(dataArray[0])+1; 
	                nextDay = new Date(dataArray[2],dataArray[1]-1,giornoCheckOut);
	    		              $('#checkoutIframe').val(nextDay.getDate()+"/"+nextDay.getMonth()+"/"+nextDay.getFullYear());  
		        $( "#checkoutIframe" ).datepicker( "option", "minDate", nextDay );
		}
	}
});