title: HTML5 mobile app running while phone screen is off?
body: <p>I'm interested in creating an HTML5 geolocation-based web app that could still be operating when the phone screen is off (say, tracking how far you've been running when your phone is in your pocket).</p>
  
  <p>Is there any way to keep the app running but have the screen be off, or have the app run in the background while other apps are being used? Is this possible at least on some of the popular mobile devices out there (newer iOS and Android devices in particular?)</p>