log beforeunload too

web/app/assets/javascripts/react-components/PopupMediaControls.js.jsx.coffee

@@ -737,6 +737,14 @@ mixins.push(Reflux.listenTo(UserStore, 'onUserChanged'))
 
     $(window).unload(@windowUnloaded)
 
+    $(window).on('beforeunload', (event) =>
+      # Cancel the event as stated by the standard.
+      #event.preventDefault()
+      #Chrome requires returnValue to be set.
+      #event.returnValue = ''
+      SessionActions.log({msg:"beforeunload", event: event})
+    )
+
     @root = jQuery(this.getDOMNode())
 
     $loop = @root.find('input[name="loop"]')