fixes #9869 (#9870)

* fixes #9869

* removed one line from code sample

aspnetcore/signalr/javascript-client.md

@@ -39,7 +39,7 @@ Reference the SignalR JavaScript client in the `<script>` element.
 
 The following code creates and starts a connection. The hub's name is case insensitive.
 
-[!code-javascript[Call hub methods](javascript-client/sample/wwwroot/js/chat.js?range=9-12,28)]
+[!code-javascript[Call hub methods](javascript-client/sample/wwwroot/js/chat.js?range=9-12)]
 
 ### Cross-origin connections
 
@@ -80,7 +80,7 @@ SignalR determines which client method to call by matching the method name and a
 
 Chain a `catch` method to the end of the `start` method to handle client-side errors. Use `console.error` to output errors to the browser's console.
 
-[!code-javascript[Error handling](javascript-client/sample/wwwroot/js/chat.js?range=28)]
+[!code-javascript[Error handling](javascript-client/sample/wwwroot/js/chat.js?range=43-45)]
 
 Setup client-side log tracing by passing a logger and type of event to log when the connection is made. Messages are logged with the specified log level and higher. Available log levels are as follows:
 
@@ -100,7 +100,7 @@ The JavaScript client for SignalR doesn't automatically reconnect. You must writ
 1. A function (in this case, the `start` function) is created to start the connection.
 1. Call the `start` function in the connection's `onclose` event handler.
 
-[!code-javascript[Reconnect the JavaScript client](javascript-client/sample/wwwroot/js/chat.js?range=30-42)]
+[!code-javascript[Reconnect the JavaScript client](javascript-client/sample/wwwroot/js/chat.js?range=28-40)]
 
 A real-world implementation would use an exponential back-off or retry a specified number of times before giving up. 
 

aspnetcore/signalr/javascript-client/sample/wwwroot/js/chat.js

@@ -39,3 +39,8 @@ connection.onclose(async () => {
     await start();
 });
 
+/* this is here to show an alternative to start, including the catch
+connection.start().catch(function (err) {
+    return console.error(err.toString());
+});
+*/