activeSheet.tables.add("Table1", 0, 0, 3, 3, GC.Spread.Sheets.Tables.TableTheme.dark1);
activeSheet.tables.add("Table2", 4, 0, 3, 3, GC.Spread.Sheets.Tables.TableTheme.medium1);
var tables = activeSheet.tables.all();
for (var i = 0; i < tables.length; i++) {
    alert(tables[i].name());
}