Hmm.. Android app exit button is a browser “back” button essentially, if I understand it correctly. If so, we need to then trap location change (back button) so we can present “are you sure that you want to exit? yes/no” dialog, with game save followed by programmatic appexit upon “yes”. Not sure if this requires Cordova, or could be done by native js means though.
WebWorkers – well, tried to grokk it, and it never worked for me. I tested webworkers on dual-core processors, and in the result both cores were 100% busy, and gui was as unresponsive as it was with single thread processing. So, webworkers were discarded, and I realized that users are happy when I display map generation percentage (%% completed) – they are okay to wait up to ~30 sec if they see what’s going on.