   play rom, extension
   .catch (e) ->
     console.error e
-    tracker.sendEvent 'error', e
+    tracker.sendEvent 'error', e if tracker?
 
 load = (file) ->
-  tracker.sendEvent 'file'
+  tracker.sendEvent 'file' if tracker?
   return if not file instanceof Blob
   draghint.classList.add 'hidden'
   reader = new FileReader()

      System.import settings.extensions[extension]
      localForage.getItem retro.md5
    ]).then ([core, save]) ->
      tracker.sendAppView 'play'
      stop() if retro.running
      retro.core = core
      core.load_game rom if rom


window.addEventListener 'drop', (event) ->
  return if draghint.classList.contains 'hidden'
  tracker.sendEvent 'drop' if tracker?
  event.preventDefault()
  draghint.classList.remove 'hover'
  if event.dataTransfer.files.length > 0
