How can update dynamically the chart by Json data?

I m biginner in nodeJs programming I had following this tutorial to create Charts using Node.js, ExpressJS and Mongodb : http://www.fusioncharts.com/dev/using-with-server-side-languages/tutorials/creating-interactive-charts-using-node-express-and-mongodb.html

but this is not the result that I would like to see because I want to do a real time chart that's updated dynamically by Json data.

I had tried to use socket. IO but she never works for me

Can you help me please

via Hassen Dakhlaoui