<input type="text" id="travel_date"/>

<script>
       $("#travel_date").datepicker({
          dateFormat: "dd-mm-yy",
          changeYear: true,
          changeMonth: true,
          numberOfMonths:[1,2],
          maxDate: $("#return_on").datepicker("getDate"),
          minDate: new Date(),
          onClose: function( selectedDate ) {
            $( "#return_on" ).datepicker( "option", "minDate", selectedDate );
            $( "#return_date" ).datepicker( "option", "minDate", selectedDate );
          }
        }).attr('readonly','readonly');
</script>

Today's date is : 19/09/2014.
     System date (I changed) : 10/09/2014