Use the automatic SignalR reconnect feature (#22694)

aspnetcore/signalr/javascript-client/samples/3.x/SignalRChat/wwwroot/chat.js

@@ -37,7 +37,13 @@ document.addEventListener("DOMContentLoaded", () => {
         }
     };
     
-    connection.onclose(start);
+    connection.onclose(function (error) {
+        if (error) {
+            console.log(`Connection closed with error: ${error}`);
+        } else {
+            console.log("Connection closed.");
+        }
+    });
 
     // Start the connection.
     start();