assert 0 if no quality data is available

ffmap/web/static/css/style.css

@@ -25,3 +25,12 @@ table.neighbours {
 .panel-heading {
 	padding: 6px 12px;
 }
+
+.graph {
+	height: 200px;
+	width: 100%;
+}
+.graph .legendLabel {
+	padding-left: 5px;
+	padding-right: 7px;
+}

ffmap/web/static/js/graph.js

@@ -81,9 +81,10 @@ function neighbour_graph(neighbours) {
 			try {
 				var quality = router_stats[i].neighbours[mac];
 				var date_value = router_stats[i].time.$date;
-				if(quality != null) {
-					data.push([date_value, quality]);
+				if(quality == null) {
+					quality = 0;
 				}
+				data.push([date_value, quality]);
 			}
 			catch(TypeError) {
 				// pass

ffmap/web/templates/router.html

@@ -12,14 +12,6 @@
 	<script src="{{ url_for('static', filename='js/graph/jquery.flot.resize.js') }}"></script>
 	<script src="{{ url_for('static', filename='js/graph.js') }}"></script>
 	<style type="text/css">
-		.graph {
-			height: 200px;
-			width: 100%;
-		}
-		.graph .legendLabel {
-			padding-left: 5px;
-			padding-right: 7px;
-		}
 		#map {
 			height: 405px;
 			width: 100%;