Does the Javascript VM that runs as part of iOS allow for program interrupt and continue?

For example, imagine a Javascript app running in Safari, containing some local in memory state, and is partway through execution (say, it's spinning an animated ball). What happens if the phone rings and I pick up? Will the animation continue from where it left off when I return to the browser?

If Safari doesn't开发者_JAVA百科 do this - is there a phone based web browser that does?

I think the animation/script will stop because I doubt that's part of background processing on iOS. I guess the animation will continue when you return to the app.

Otherwise a badly coded script might drain your battery even if Safari is not the active app.

The current javascript vm does not seem to allow for this.