var today = new Date();
  	var tomorrow = today;
	  tomorrow.setDate(today.getDate() + 1);

	  function attachCalendar(form_id) {
      $('#' + form_id + '-checkin').attr("readonly", true);
      $('#' + form_id + '-checkout').attr("readonly", true);

  	  $('#' + form_id + '-checkin').datepicker({
				dateFormat: "yy-mm-dd", 
				yearRange: "-0:+1", 
        numberOfMonths: 2,
				minDate: today, 
				showOn: "both", 
				buttonImage: "calendar.gif", 
				buttonImageOnly: true, 
				onSelect: function(date) { 
					var ds = $.datepicker.parseDate('yy-mm-dd', date); 

          var deo = $('#' + form_id + '-checkout');
          var change = true;
					if (deo.val() != '') {
						var de = $.datepicker.parseDate('yy-mm-dd', deo.val()); 
						if (ds.getTime() < de.getTime()) { 
              change = false;
            }
					} 

				  if (change) {
						ds.setDate(ds.getDate() + 1); 
						deo.val($.datepicker.formatDate('yy-mm-dd', ds)); 
          }
				}
			});

  		$('#' + form_id + '-checkout').datepicker({
				dateFormat: "yy-mm-dd", 
				yearRange: "-0:+1", 
        numberOfMonths: 2,
				minDate: tomorrow, 
				showOn: "both", 
				buttonImage: "calendar.gif", 
				buttonImageOnly: true, 
				onSelect: function(date) { 
					var de = $.datepicker.parseDate('yy-mm-dd', date); 

          var dso = $('#' + form_id + '-checkin');
          var change = true;
					if (dso.val() != '') {
						var ds = $.datepicker.parseDate('yy-mm-dd', dso.val()); 
						if (ds.getTime() < de.getTime()) { 
              change = false;
            }
					} 

				  if (change) {
						de.setDate(de.getDate() - 1); 
						dso.val($.datepicker.formatDate('yy-mm-dd', de)); 
          }
				}
			});
    }