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 row filter.
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();
    if (rowFilter.isFiltered(0)) {
        alert("Row-filtering executed for Column1");
    } else {
        alert("Row-filtering not executed for Column1");
    }
});
//Add button control to page
<input type="button" id="button1" value="button1"/>