I've recently started learning to use the D3.js framework and, while it seems like it's been designed to do exactly what I want, I can't find a simple example of a "live" updating graph.

I'm looking for something like a line chart that updates as new data becomes available. New data would be obtained either by hitting a json url with a "last seen" timestamp or some other AJAX-y method.

edit: The D3 part of the answer is here:

http://bost.ocks.org/mike/path/

Now, how do people recommend getting the new data from the server to the client?

d3.js
Edit
Report