I have a jquery datepicker script and what I want to do is to change "minDate: 10" value by a select box.

$(function() {
    $('#hotel').change(function() {
        // assign the value to a variable, so you can test to see if it is working
        var selectVal = $('#hotel :selected').val();
        if( selectVal == "hotel_c" ) {
            var date = 10;
        }
        if( selectVal == "hotel_a" ) {
            var date = 15;
        }
        if( selectVal == "hotel_b" ) {
            var date = 6;
        }
    });
    var dates = $('#from, #to').datepicker({
        defaultDate: "+1w",
        changeMonth: true,
        dateFormat: 'yy-m-d',
        minDate: 10,
        numberOfMonths: 3,
        onSelect: function(selectedDate) {
            var option = this.id == "from" ? "minDate" : "maxDate";
            var instance = $(this).data("datepicker");
            var date = $.datepicker.parseDate(instance.settings.dateFormat || $.datepicker._defaults.dateFormat, selectedDate, instance.settings);
            dates.not(this).datepicker("option", option, date);
        }
    });
});

?