slight refactor.

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

@@ -234,12 +234,13 @@ var regionChooser = (function(){
 			dataPanel.prepend("<h2 class='error'>Sorry, the CityGML files should all be written with the same coordinate system.</h2><br/>\n");
 		}
 		
+		document.documentElement.className = 'wait';
+		
 		var citygmlNames = features.map(f => f.get("name"));
 		// Waiting 100ms in order to let the cursor change
 		setTimeout(function() {
 			var start = new Date().getTime();
 			if (proj4.defs(srsName)){
-				document.documentElement.className = 'wait';
 				console.log("Selected region is written in " + srsName + " coordinate system.");
 				try {
 					fxapp.downloadRegionFromCityGMLs(sketchAsWKT(srsName), project, citygmlNames.join(";"), srsName);
@@ -374,13 +375,10 @@ var regionChooser = (function(){
 	}
 	
 	publicScope.downloadFromSelectedCityGMLs = function() {
+		document.getElementById("download_region_button").disabled = true;
 		var checkedBoxes = Array.from(document.querySelectorAll("input.select_citygml")).filter(c => c.checked);
-		if (checkedBoxes.length === 0){
-			console.log("You should select at least one citygml, though.");
-		} else{
-			document.getElementById("download_region_button").disabled = true;
-			publicScope.downloadRegionFromCityGMLs(checkedBoxes.map(c => c.id));
-		}
+		// CheckBoxes isn't empty, because otherwise the button cannot be clicked.
+		publicScope.downloadRegionFromCityGMLs(checkedBoxes.map(c => c.id));
 	}
 	
 	publicScope.checkCityGMLS = function(allOrNone) {