From Servoy 8.4 on, all client side messages from the browser's Console loggers (log (is send as info),error,info,warn,debug) will be send to the server and logged through the logger: org.sablo.BrowserConsole. By default this is not configured in the log4j.xml file so it logs WARN and ERROR messages from the browser. This could be adjusted by adding a logger:
<Logger name="org.sablo.BrowserConsole" level="INFO" />
by making it INFO you will see also Console.log and Console.info
You can also redirect this to a another file, see Websocket Message logging (for debug purposes) for another sample how to do that.
Besides the Console object of the browser, also the global Window.onerror is catched and logged as error to the browser