if user disconnects, remove complete

public/js/index.js

@@ -8,3 +8,8 @@ button.addEventListener('click', (event)=>{
     button.setAttribute("disabled",true);
     socket.emit('prompt completed');
 });
+window.addEventListener("beforeunload", (e)=>{
+    if(button.getAttribute("disabled")){
+        socket.emit('remove completed');
+    }
+});

server.js

@@ -23,6 +23,10 @@ socketserver.on('connection', (socket)=>{
         currentComplete++;
         socketserver.emit('prompt completed', currentComplete);
     });
+    socket.on('remove completed', ()=>{
+        currentComplete--;
+        socketserver.emit('prompt completed', currentComplete);
+    });
 });
 
 http.listen(PORT);