This way your doing the graphical stuff on the client. This is possible but still the Arduino with the RN-XV is limited to about 10kB/s because it's communicating over the USART with the Arduino. The libraries folder of RGraph.net is about 1.6 MB. If the client has to pull all the stuff contained there it needs about 3 minutes just to get that from the Arduino. So although your idea is possible it's not practical. If you use another web server and just get the data from the Arduino, you're fine because transferring the data doesn't need that much bandwidth.