activeSheet.setRowCount(7);
activeSheet.setValue(0, 0, "North");
activeSheet.setValue(1, 0, "South");
activeSheet.setValue(2, 0, "East");
activeSheet.setValue(3, 0, "South");
activeSheet.setValue(4, 0, "North");
activeSheet.setValue(5, 0, "North");
activeSheet.setValue(6, 0, "West");
activeSheet.setColumnWidth(0, 80);

//Set a rowFilter.
activeSheet.rowFilter(new GC.Spread.Sheets.Filter.HideRowFilter(new GC.Spread.Sheets.Range(0, 0, 7, 1)));

$("#button1").click(function () {
    var rowFilter = spread.getActiveSheet().rowFilter();
    //*********************************************
    //Exit if Column1 has not been filtered.
    //*********************************************
    if (!rowFilter.isFiltered(0)) {
        return;
    }

    //*********************************************
    //Filtered strings
    //*********************************************
    var filterItems = rowFilter.getFilterItems(0);
    var str = "Filtered strings:";
    filterItems.forEach(function (item) {
        str += " " + item.expected();
    });

    console.log(str);
    console.log(" ");

    //*********************************************
    //Number of Filtered-In (displayed) rows
    //*********************************************
    var range = rowFilter.range;
    var filteredInRows = [], filteredOutRows = [];
    for (var i = range.row, last = range.row + range.rowCount; i < last; i++) {
        if (rowFilter.isRowFilteredOut(i)) {
filteredOutRows.push(i);
        } else {
filteredInRows.push(i);
        }
    }
    console.log("Number of Filtered-In (displayed) rows: " + filteredInRows.length);
    console.log(" ");

    //*********************************************
    //Number of Filtered-Out (hidden) rows
    //*********************************************
    console.log("Number of Filtered-Out (hidden) rows: " + filteredOutRows.length);
    console.log("");

    filteredOutRows.forEach(function (item) {
        console.log("Filtered-Out (hidden) row index: " + item);
    });
    console.log(" ");

    //*********************************************
    //Filtered-In (displayed)/Filtered-Out (hidden) rows
    //*********************************************
    filteredOutRows.forEach(function (item) {
        console.log("Data of Filtered-Out (hidden) row: " + activeSheet.getValue(item, 0));
    });
    console.log(" ");
    filteredInRows.forEach(function (item) {
        console.log("Data of Filtered-In (displayed) row: " + activeSheet.getValue(item, 0));
    });
});

//Add button controls to page
<input type="button" id="button1" value="button1"/>