It may not be 100% reliable, but coupled with other techniques (catching error 404s etc) this provides a nice way to inform the user that their connection to ou

It may not be 100% reliable, but coupled with other techniques (catching error 404s etc) this provides a nice way to inform the user that their connection to our application may be gone. For single page apps that use browser storage and sync to the remote periodically it is great to be able to inform the user that "Hey you're offline. You can keep using it, but your changes won't be available for others to see until you re-connect".