I could be very useful to web apps to know when we are using too much memory, such that we're at risk of being killed. One idea is to provide a 'low memory' event via a JS page event, which could allow an app to free any spare memory and/or scale back its memory usage. An app could unlink spare objects it doesn't need anymore. After returning from this event, JS could GC/CC (as normal for memory pressure events, I think) to free whatever memory the page could spare. With this API, a page would be able to respond to dangerous levels of memory use. Currently, if an app uses a lot of memory on mobile, it risks the OS axing the browser for using too much memory.

Yeah, good idea; we already have some of the data, so we should be able to expose it to web apps. Useful for more than just games, too.

It'd be good to check with other browsers on standard mailing-lists before proceeding. The WHATWG mailing list sounds like a good fit for this sort of feature. http://lists.whatwg.org/listinfo.cgi/whatwg-whatwg.org

Low memory notifications would also be useful for B2G apps.