Alert on websocket close

app/www/draw.js

@@ -119,7 +119,7 @@ class Canvas {
         this.setColor(this.colors[0]);
 
 
-        this.socket = new WebSocket(this.url);
+        this.socket = new WebSocket(this.url); // TODO: reconnectingwebsocket
         this.socket.addEventListener('open', (e) => {
             this.sendDimensions();
 
@@ -150,6 +150,10 @@ class Canvas {
                 // this.openTheFloor()
             }
         });
+        this.socket.addEventListener('close', (e) => {
+            this.closeTheFloor();
+            alert('Internet connection seems to have problems. Please reload the page to reconnect.');
+        });
     }
 
     setPreloaded(json_url) {
@@ -207,6 +211,10 @@ class Canvas {
         this.wrapperEl.classList.remove('closed');
     }
 
+    closeTheFloor() {
+        this.wrapperEl.classList.add('closed');
+    }
+
     setFilename(filename) {
         this.filename = filename;
         this.filenameEl.innerText = filename;