javascript - How can I detect shutdown of a cached iPhone app? -

i have iphone webapp uses cache manifest work offline , add webapp home screen. find way detect app exiting can housekeeping , save data.

if running web page in safari, window.onunload me, event not happen when running home screen.

i tested pagehide event using below code , found works detecting whether user navigated link or opened new tab when in safari.

however, if in web app saved homescreen (like describe) pagehide event useless telling if web app closed.

depending on need specifically, can work around limitation saving data localstorage , checking localstorage when app opens again. can perform work may need done before app starts again.

function myloadhandler(evt) {   if (evt.persisted) {     alert('user returns page tab');     return;   }   alert('loading new page'); }  function myunloadhandler(evt) {   if (evt.persisted) {     alert('user goes new tab');     return;   }   alert('user leaves page'); }  if ("onpagehide" in window) {   window.addeventlistener("pageshow", myloadhandler, false);   window.addeventlistener("pagehide", myunloadhandler, false); } else {   window.addeventlistener("load", myloadhandler, false);   window.addeventlistener("unload", myunloadhandler, false); }