i saw a site linked on HN that was using that kind of technique to siplay public camera feeds, if anyone remember the link , would be great to share it again.
They're very easy to find as most vendors have a URL pattern. For example, here're a bunch of public security cameras made by Axis: https://www.google.com/#output=search&q=inurl:axis-cgi%2...
Don't know why it was taken down. Here is the old thread : https://news.ycombinator.com/item?id=5543465
which mentions the Content-Type "multipart/x-mixed-replace" technique used to constantly update jpegs in the browser.