iOS8 issues I have come across

For a more complete list check out apple shows love for html5

Debug

• No inspector when using mobile safari and pluged in iOS device.
• Inspector works for home screen apps.

Look and feel

• window.scrollTo(0, 1); doesn't hide the url bar anymore.
• Landscape causes the status bar to sometimes disappear (iPhone 5). Don't know if feature or bug.
• fixed and absolute dom elements. This has from day 1 been broken. Now it's broken in new ways...
• On iPad2 the cellular + battery status bar is sometimes black and sometimes white.

Misc

WKWebView cannot load files using file:// URL protocol since iOS 8 beta 4 and 5

Homescreen

• html5 video doesn't work at all, for example using youtube's embed iframe it never plays. (still broken in IOS 8.1.1)
• window.indexedDB is there, set to null and is a READONLY property. Breaking shims/feature detection. (https://github.com/JamesKyburz/IndexedDBShim/commit/a254fdddb4880af4afee79f8984574eda7b09d09) fixes this if used in combo with idb-wrapper.
• calling prompt/alert in the same tick in the event loop for (click/touch) causes safari to crash with EXC_CRASH (SIGABRT) The fix for this is not ideal because calling prompt in setTimeout doesn't show the keyboard.....
• locking and unlocking device removes all javascript timers! event listeners are intact, however even a location.reload() doesn't fix this issue. You are left with a mobile safari in an unusable state! My fix was to abuse the other alert bug, you will need your own implementation of ping.

  //iOS8 deletes all timers and leaves mobile safari in an unusable state.
  if (window.navigator.standalone) {
    document.addEventListener('touchmove', heartBeat, false);
    ping();
  }
  
  function ping() {
    // when timers are removed session.get will never call the callback
    setTimeout(session.get.bind(session, 'ping', ping), 1000);
    ping.i = new Date();
  }
  
  function heartBeat() {
    if (new Date() - ping.i > 4000) {
      // this will crash mobile safari because of another bug, this it what we want in this case though ;)
      alert('Some helpful text, blah blah');
    }
  }