Optimized for what? You started the thread because it's too slow. If it doesn't depend on the server, where does it get the data for the refresh? SignalR there is no loop. The data is pushed to the client when there's something new. Polling as you're describing is an older technology. Web Sockets is the way to go and Signal R is the way to do it.

>This is executed in memory of the browser, as is, so it is not dependant on the server nor to any other third party or architecture. Once the DIV content of each item loaded, the rest is executed locally. This satisfies our needs. We just wanted to see about optimization. For now, I have defined the date created by new Date() once, as well as its millisecond equivalent, thus before calling in a loop the refresh of those times. That seems to help as it does not have to create a new date at every loop, nor to obtain its milliseconds.