Detect closing of mobile Safari

I'm building a WebApp which uses video server push with:

<img id="vidsrc" src="video.cgi"/>

It works. And when saved as a WebApp using "Add to Home Screen" closing the app does as expected and stop receiving the server push.

However when running in mobile Safari, only closing the page will get it to stop. What I'm trying to figure out is how to get it to stop if the user clicks the Home button and closes mobile Safari so the push doesn't keep running in the background.

Because of what I've got to work with, editing video.cgi is not an option. And using video.cgi in an iframe isn't a good solution because of some other functionality in the page/app.

onBlur and onClose don't seem to do it, a开发者_如何学JAVAnd I'm wondering if there's any way an HTML page or the good stuff in it can know that mobile Safari has been closed.

Unfortunately, you can't... Web apps are not allowed to access the device's software, so are not told when you have pressed the button.