I have been under the impression that http://localhost:50000/preview.html is a local. When my ISP went down last night for the next 12h, I realized that I was unable to do the HTML5 preview. Accessing that page only result in a down connection message. The ISP modem has no connection, but the internal network was still functioning for everything else. Still, this is local only, right? Am I wrong? Should it still have been working?