I'm building a very simple app that relies on a remote server. I will use this app on many websites, so I decided to store it on one server (I have control of the remote server in question).

I need to make sure that this server is up and running, so in the case it's not I can use a fallback.

Would it be a client-side approach? A server-side approach? My guess is to use a js snippet to do the job. If I'm correct, I'll probably use jquery to perfom the task.