var defaultStyle_polygon_1 = new ol.style.Style({
            fill: new ol.style.Fill({
                color: 'rgba(251, 209, 88, 0.4)'
            }),
            stroke: new ol.style.Stroke({
                color: 'rgba(251, 209, 88, 1)',
                width: 2
            }),
        });

        var openstreetmap = new ol.layer.Tile({
                    source: new ol.source.OSM()
                });


                    var polygon_source = new ol.source.Vector({
                        format: new ol.format.GeoJSON(),
                        url: function(extent, resolution, projection) {
                        return 'https://fbinter.stadt-berlin.de/fb/wfs/geometry/senstadt/re_schutzgebiete?service=WFS&' +
                            'version=2.0.0&request=GetFeature&typeNames=re_schutzgebiete&' +
                            'outputFormat=application/json&crs=EPSG:25833&' + 'Filter=%3CFilter%3E%3CPropertyIsEqualTo%3E%3CPropertyName%3ESCHUTZSTATUS%3C/PropertyName%3E%3CLiteral%3EFFH-Gebiet%3C/Literal%3E%3C/PropertyIsEqualTo%3E%3C/Filter%3E';
                        },
                        strategy: ol.loadingstrategy.tile(ol.tilegrid.createXYZ({
                            minZoom: 10
                        }))
                    });

        var polygons = new ol.layer.Vector({
                    source: polygon_source,
                    style: defaultStyle_polygon_1
                });

        var map = new ol.Map({
            target: 'map',
            layers: [
                    openstreetmap,
                    polygons
            ],
            view: new ol.View({
                center: ol.proj.transform([13.3833, 52.5167], 'EPSG:4326', 'EPSG:3857', 'EPSG:25833'),
                zoom: 9,
            }),
        });

var select = new ol.interaction.Select({});
map.addInteraction(select);


var search = new ol.control.SearchFeature(
    {
        source: polygon_source,
        property: "GEBIETSNAME"
    });
map.addControl (search);

var selectedFeatures = [];
    selectFeaturesGlobal = selectedFeatures;

search.on('select', function(e)
    {   select.getFeatures().clear();
        select.getFeatures().push (e.search);
        var p = e.search.getGeometry().getFirstCoordinate();
        map.getView().animate({
            center: p,
            zoom: 13
        });
    });

search.on('select', function(event)
    {
            var selectedFeatures = [];
            selectFeaturesGlobal = selectedFeatures;

            map.forEachFeatureAtPixel(event.pixel, function(feature, layer) {
                console.log(feature.get('GEBIETSNAME'));
                selectedFeatures.push(feature);
            });
            if (selectedFeatures.length > 0) {
                var info = [];
                for (var i=0; i<selectedFeatures.length; i++) {
                    info.push(selectedFeatures[i].get('GEBIETSNAME'));
                }
                <!-- string aus der Liste erzeugen 'info.join'-->
                document.getElementById('infoDiv').innerHTML = info.join('<br />')
            } else {
                <!-- wenn kein Feature ausgewählt wird, wird nichts angezeigt -->
                document.getElementById('infoDiv').innerHTML = '';
            }
    });