$(function() {
    $( "#datepicker" ).datepicker({
        numberOfMonths: 3,
        mode: 'range',
        changeMonth: true,
        showButtonPanel: false,
        minDate: 0,
        onSelect: function() {
            function(dateText, inst) {
                var date1 = $.datepicker.parseDate($.datepicker._defaults.dateFormat, $('#start-date').val());
                var date2 = $.datepicker.parseDate($.datepicker._defaults.dateFormat, $('#end-date').val());
                if (!date1 || date2) {
                    $('#start-date').val(dateText);
                    $('.start-date-visible').text(dateText);
                    $('#end-date').val('');
                    $('.end-date-visible').text('');
                    $(this).datepicker('option', dateText);
                } else {
                    $('.end-date-visible').text(dateText);
                    $('#end-date').val(dateText);
                    $(this).datepicker('option', null);
                }
            }
            function() {
                //here is second function
            }
        }
    });
});