Write A Class Or Function That Controls Stats On Page?

I am trying to write a class or function (not sure which is needed) that controls stats on my page. I currently have a working example but I need additional functionality and I'm not sure how to do it. Basically it needs to run every 6 seconds to update the stats(as they change constantly).

I need the javascript to connect(using ajax) to a database and retrieve stats to initially store as global variables. Then, as stated, I need it to modify(simple math that I can do) these stats every 6 seconds.