enter code here
        from = $( "#from" ).datepicker({
              showOn: "button",
            buttonImage: "images/calendar_icon-32x32.png",
            buttonImageOnly: true,
            buttonText: "From date",
        changeMonth: true,
                    dateFormat: 'dd/mm/yy',
                    onSelect: function(mindata) {
                        if (mindata != dalla_data) {
                            dalla_data = mindata;
                        };
                        window.location.href = "http://index.php?ricid=1&modo=1&tiporic=2&prg=gesric#gesric_form";
            }
    }).on( "change", function() {
        to.datepicker( "option", "minDate", getDate( this ) );
          display("Got change event from field");
    }),
  to = $( "#to" ).datepicker({
              showOn: "button",
            buttonImage: "images/calendar_icon-32x32.png",
            buttonImageOnly: true,
        changeMonth: true,
                dateFormat: 'dd/mm/yy',
                buttonText: "To date",
                onSelect: function(maxdata) {
                    if (maxdata != alla_data) {
                        alla_data = maxdata;
                    };
                        window.location.href = "http://index.php?ricid=1&modo=1&tiporic=2&prg=gesric#gesric_form" + this.value;
        }
    }).on( "change", function() {
        from.datepicker( "option", "maxDate", getDate( this ) );
    });
            $("#from").datepicker('enable');
            $("#to").datepicker('enable');

function getDate( element ) {
  var date;
  try {
    date = $.datepicker.parseDate( dateFormat, element.value );
  } catch( error ) {
    date = null;
  }

  return date;
}

<a class="ui-state-default ui-state-active" href="#">