Trying many stuff. Checklist instead of single link.

src/main/resources/eu/simstadt/regionchooser/website/script/simstadt_openlayers.js

 var regionChooser = (function(){
 	var publicScope = {};
 	var fromJavaFX = navigator.userAgent.indexOf('JavaFX') !== -1;
+	//NOTE: Could do without jQuery
 	var dataPanel = $('#dataPanel');
 	var wgs84Sphere = new ol.Sphere(6378137);
 	var gmlId = 0;
@@ -9,21 +10,21 @@ var regionChooser = (function(){
 		$("html").addClass("wait");
 	}
 
-    // Hash function
-const cyrb53 = (str, seed = 0) => {
-  let h1 = 0xdeadbeef ^ seed,
-    h2 = 0x41c6ce57 ^ seed;
-  for (let i = 0, ch; i < str.length; i++) {
-    ch = str.charCodeAt(i);
-    h1 = Math.imul(h1 ^ ch, 2654435761);
-    h2 = Math.imul(h2 ^ ch, 1597334677);
-  }
-  
-  h1 = Math.imul(h1 ^ (h1 >>> 16), 2246822507) ^ Math.imul(h2 ^ (h2 >>> 13), 3266489909);
-  h2 = Math.imul(h2 ^ (h2 >>> 16), 2246822507) ^ Math.imul(h1 ^ (h1 >>> 13), 3266489909);
-  
-  return 4294967296 * (2097151 & h2) + (h1 >>> 0);
-};
+    // Hash function. For testing purposes in browser (no Feature ID is available)
+	const cyrb53 = (str, seed = 0) => {
+	  let h1 = 0xdeadbeef ^ seed,
+		h2 = 0x41c6ce57 ^ seed;
+	  for (let i = 0, ch; i < str.length; i++) {
+		ch = str.charCodeAt(i);
+		h1 = Math.imul(h1 ^ ch, 2654435761);
+		h2 = Math.imul(h2 ^ ch, 1597334677);
+	  }
+	  
+	  h1 = Math.imul(h1 ^ (h1 >>> 16), 2246822507) ^ Math.imul(h2 ^ (h2 >>> 13), 3266489909);
+	  h2 = Math.imul(h2 ^ (h2 >>> 16), 2246822507) ^ Math.imul(h1 ^ (h1 >>> 13), 3266489909);
+	  
+	  return 4294967296 * (2097151 & h2) + (h1 >>> 0);
+	};
 
 	var osm_layer = new ol.layer.Tile({
 		source: new ol.source.OSM()
@@ -173,12 +174,13 @@ const cyrb53 = (str, seed = 0) => {
 		// TODO: Add checkbox + label + 
 		// TODO: Add submit.
         // TODO: If possible, highlight the corresponding polygon when hovering above a name.
+        console.log("Feature name : "+ feature["name"]);
+        console.log("Feature ID : "+ feature.getId());
 		if (fromJavaFX) {
-			link += "<a href=\"#\" onclick=\"regionChooser.downloadRegionFrom" + feature["source"] + "(" + feature.getId()
-					+ ");return false;\">" + feature["name"] + "</a>";
+			link += '<input type="checkbox" id="check_' + feature.getId() + '" class="select_citygml"><label for="check_' + feature.getId() + '">' +  feature['name'] + '</label>';
 		} else {
             h = cyrb53(feature['name']);
-			link += '<input type="checkbox" id="check' + h+ '"><label for="check' + h + '">' +  feature['name'] + '</label>';
+			link += '<input type="checkbox" id="check_' + h+ '" class="select_citygml"><label for="check_' + h + '">' +  feature['name'] + '</label>';
 		}
 
 		link += " (" + citygml_percentage + "%";
@@ -201,9 +203,10 @@ const cyrb53 = (str, seed = 0) => {
 		var polygonArea = sketch.getGeometry().getArea();
 		var intersection_found = false;
 		intersections.clear();
+		//NOTE: getFeatures seems to not be sorted anymore. :-/
 		features_by_project = groupBy(kml_source.getFeatures(), "project");
 		
-		Object.keys(features_by_project).sort().forEach(function(project) {
+		Object.keys(features_by_project).forEach(function(project) {
 		    features = features_by_project[project];
 		    features_and_intersections = features.map(f=> [f, findIntersection(f,polygon)]).filter(l => l[1] !== undefined);
 		    if (features_and_intersections.length > 0){
@@ -213,7 +216,11 @@ const cyrb53 = (str, seed = 0) => {
 		    }
 		});
 		
-		if (!intersection_found) {
+		if (intersection_found) {
+			document.getElementById("download").style.visibility = 'visible';
+		}
+		else {
+			document.getElementById("download").style.visibility = 'hidden';
 			dataPanel.append("No intersection found with any CityGML file.<br/>\n");
 		}
 	}
@@ -272,6 +279,8 @@ const cyrb53 = (str, seed = 0) => {
 			dataPanel.append(wgs84_coords + "<br/>\n");
 		}
 		dataPanel.append("<h3 class='clean'>Area : " + (area / 10000).toFixed(1) + " ha\n");
+		dataPanel.append('<button type="button" onclick="regionChooser.clickety_click()" id="download" style="visibility:hidden">Download Region</button>');
+		dataPanel.append('<br/>\n');
 		findIntersections();
 	}
 
@@ -352,6 +361,11 @@ const cyrb53 = (str, seed = 0) => {
 		$("html").removeClass("wait");
 		console.log("READY!");
 	}
+	
+	publicScope.clickety_click = function() {
+		console.log("You clicked pretty well");
+		document.querySelectorAll("input.select_citygml").forEach(x => console.log(x));
+	}
 
 	focusOnMap();
 	//var regionChooser = publicScope; //NOTE: In order to open closure. For debugging